Chapter XIV (1)

THE MICROSAURIAN FAMILY TUDITANIDÆ, FROM THE COAL MEASURES OF OHIO AND PENNSYLVANIA.

=Family TUDITANIDÆ Cope, 1875.=

Cope, Geol. Surv. Ohio, II, pt. II, p. 357, 1875.

Lizard-like microsaurians; cranial elements strongly sculptured
with pits or grooves or almost smooth, with weak punctulations.
Orbits usually well forward; squamosal sometimes excluded from the
parietal; skull hornless; teeth pleurodont, conical and sharp,
smooth or slightly plicate; clavicle of a triangular shape, which
is characteristic of all the species; vertebræ well developed and
phyllospondylous, the osseous portion being merely a hollow cylinder,
hour-glass-shaped; ribs curved, long, attenuated and intercentral;
digits clawed; ventral armature absent in all but a single species and
the association of the species is doubtful; tail moderate in length.
Three genera with 13 species included in the family. These species are:

_Tuditanus punctulatus_ Cope, Linton, Ohio.
_brevirostris_ Cope, Linton, Ohio.
_longipes_ Cope, Linton, Ohio.
_minimus_ Moodie, Cannelton, Pennsylvania.
_walcotti_ Moodie, Linton, Ohio.
_Erpetosaurus radiatus_ Cope, Linton, Ohio.
_obtusus_ Cope, Linton, Ohio.
_tabulatus_ Cope, Linton, Ohio.
_minutus_ Moodie, Cannelton, Pennsylvania.
_sculptilis_ Moodie, Cannelton, Pennsylvania.
_acutirostris_ Moodie, Linton, Ohio.
_tuberculatus_ Moodie, Linton, Ohio.
_Odonterpeton triangularis_ Moodie, Linton, Ohio.

The association of these species in the one family is provisional and will need revision on the acquisition of new and more complete material.

=Genus TUDITANUS Cope, 1874.=

Cope, Trans. Amer. Phil. Soc., XV, p. 271, 1874.

Cope, Geol. Surv. Ohio, II, pt. II, pp. 391, 1875.

Type: _Tuditanus punctulatus_ Cope.

The genus as here defined is a somewhat composite group and it is quite probable that some of the species here included will have to be removed to another genus when the anatomy of the forms is better known. The species of the genus are all moderately small, the largest barely attaining a length of 8 inches.

There are 5 species of Tuditanus thus far known. All of the species are characterized by the possession of a peculiar triangular-shaped clavicle with radiating grooves, and this has been taken as one of the distinctive characters of the genus, as well as of the family. The structure of the cranium where known is quite uniform among the different species. The squamosal is quite large and the supratemporal is not always closely joined to the parietal. The species are:

_Tuditanus punctulatus_ Cope, Linton, Ohio.
_brevirostris_ Cope, Linton, Ohio.
_longipes_ Cope, Linton, Ohio.
_minimus_ Moodie, Cannelton, Pennsylvania.
_walcotti_ Moodie, Linton, Ohio.

=Tuditanus punctulatus Cope.=

Cope, Trans. Amer. Phil. Soc., XV, p. 271, 1874.

Cope, Geol. Surv. Ohio, II, pt. II, p. 392, pl. xxxiv, fig. I, 1875.

Type: Specimen No. 110, American Museum of Natural History, where there is also specimen No. 111.

Horizon and locality: Linton, Ohio, Coal Measures.

This species, together with the form, _T. brevirostris_, described on p. 88, was used by Cope as the type of the genus _Tuditanus_. Cope subsequently associated some reptilian remains from the Linton mines with the type of _T. punctulatus_ and changed the generic term to _Isodectes_, which was known by another species, _I. megalops_ Cope, from the Permian of Texas. The remains associated by Cope with _I. megalops_ undoubtedly represent a reptilian species and which has been described elsewhere under the name _Eosauravus copei_ Williston. The species is of exceeding interest because it is the _oldest known reptile_ and places the range of the Reptilia down towards the base of the Pennsylvanian.

The species _Tuditanus punctulatus_ Cope was founded on well-preserved remains of nearly the entire skeleton of a single individual. The bones are represented by shining carbonaceous matter, and since both of the slabs containing the impression were preserved, a great many characters have been determined. The head, 1 fore-limb, and 23 consecutive vertebræ with ribs are well defined, but of the pelvis and hind limbs nothing is visible.

The cranium (fig. 19) is very similar to that of _T. minimus_, from the Cannelton, Pennsylvania, slates. It is triangular in shape, with a narrowed obtuse muzzle. The orbit of the left side is well defined and lies well forward. It is oval in outline and its width is about two-thirds of its length. The nostrils are small and are located well toward the tip of the muzzle. The parietal foramen lies behind the median transverse line which divides the skull equally.

The cranial elements are for the most part destroyed, but the outlines of a few can be determined. Those elements which are preserved are ornamented with a sculpturing of minute punctulations which, on the postfrontal, assumes a radiating arrangement. The ornamentation of the other elements consists of inosculating pits, but they seldom assume the form of ridges or grooves. The bones of the premaxillary region of the cranium are lacking. The first element which can be detected is the pref rental, which occupies a position in front of the orbit. There seems to be space for a lacrimal, but its outline is not distinct. The frontal can be readily separated and is seen to be an elongate element occupying the median region of the skull between the orbits. The parietal is apparently the largest element of the cranial roof and the pineal foramen is located in the anterior fourth of the median suture separating the parietal elements. The form of the postparietal and the tabulare can not be determined, as the greater part of this region is lacking. The squamosal seems to be located well forward and is rather small, but has the usual relation of this element. Only fragments of the other elements remain and nothing can be said of their form. The mandibles of both sides are represented by depressions, and they are ornamented with longitudinal grooves and ridges. The teeth are not preserved, but there are evidences of the maxillary teeth. These are minute and sharply conical. Just posterior to the skull there is preserved the impression of a short, round rod which is not definitely determined. It may be an element of the hyoid apparatus, although it is rather stout for such. It does not have the relations indicated by Cope in his figure (123, pl. XXXIV, fig. 1).

There are three elements of the pectoral girdle preserved. These undoubtedly represent the interclavicle and the clavicles. The interclavicle is rhomboid in shape and is attenuated posteriorly. The attenuation is abruptly truncate posteriorly and it is thus of quite a different character from the acutely pointed interclavicle of _T. minimus_. The clavicle has a somewhat semicircular form, but is not attenuated at either end. It seems to be uniformly broad.

The forearm of the right side is preserved in part. The humerus is seen to be a heavy, somewhat expanded element lying displaced with relation to the pectoral girdle. It is greatly expanded at the ends. The ulna presents characters similar to the humerus and only differs from it in being shorter and less stout. The radius is not preserved. The carpus is unossified and its position is occupied by a blank space. The digits are represented by 4 metacarpals, and this may have constituted the entire number of the fingers. The phalangeal bones preserved are a little scattered. They are elongate with expanded ends.

Evidences of 23 consecutive osseous vertebræ are preserved. Their character can not be determined, although Cope (123) describes them as amphicœlous. This may be inferred to be the case, but I am unable to verify his observation. In form the vertebra are subquadrate. The neural spines are not evident. The osseous ribs articulate, apparently, between the bodies of the vertebra. Cope figured them as intercentral. There are 22 or 23 pairs preserved. They are single-headed and the extremities are attenuated. No traces of ventral scutellæ are present.

The entire length of the animal probably did not exceed 5 or 6 inches. Its form was quite lizard-like and it was probably of an ambulatory type, though it may have spent a part of its time in the old lagoon in which its remains were finally buried. No traces of external gills have been detected in this or any other Linton species.

Measurements of the Type of Tuditanus punctulatus Cope.

mm.
Length of entire specimen 94
Median length of skull 22
Width of skull at occiput 19
Depth of mandibular ramus 4
Length of the 23 vertebræ 61
Length of interclavicle 6.5
Width of interclavicle 4.5
Width of the three pectoral plates 10
Length of humerus 8
Width of humerus at proximal end 2.5
Length of ulna 6
Width of ulna at proximal end 2
Length of phalanx (metacarpal?) 2
Expanse of longest ribs 16
Length of rib 10.5
Width of rib .5
Length of a vertebra 2.5

=Tuditanus brevirostris Cope.=

Cope, Trans. Amer. Phil. Soc., XV, p. 272, 1874.

Cope, Geol. Surv. Ohio, II, pt. II, p. 393, pl. xxvi, figs. 3, 4, 1875.

Moodie, Bull. Amer. Museum Natl. Hist., XXVI, art. XXV, pl. lxiv, fig.
4, 1909.

Type: Specimen No. 8609 G, American Museum of Natural History.

Horizon and locality: Linton, Ohio, Coal Measures.

This species was associated by Cope with the type _T. punctulatus_ in the description of the genus. Represented by a portion of the skeleton of one individual, the skull is preserved on one block, with a considerable part of the anterior ribs, pectoral girdle, and vertebral column, although this last is not clearly represented, but as in so many of the coal specimens the bones are covered with a thin layer of carbonaceous matter which makes it impossible to definitely determine the form.

The cranium is large in proportion to the size of the body. The skull is in the form of a wide oval and is wider than it is long. The elements of the skull were ornamented with a coarse sculpturing which partakes of the nature of incomplete radiations on the squamosal region. The different elements of the cranium can not be distinguished, although I think the outlines of the parietal are indicated. The position of the nostrils is well forward and they are slightly elongate transversely. The pineal foramen can not be determined. The orbits are oval in shape and their width is about equal to two-thirds of their length. The interorbital space is greater than the length of the orbit. Cope's figure of this specimen is not accurate, since he has the orbits drawn too far to the side. They are located near the central line of the skull and resemble in some respect those of the preceding species. Cope has described teeth in the maxillary region, but I am unable to detect them. There are portions of two pectoral elements which may represent a clavicle and a portion of the interclavicle.

The clavicle has much the same shape and practically the same ornamentations as has the clavicle in _Tuditanus minimus_. The clavicle preserved shows a somewhat triangular shape and is slightly acuminate at the anterior end, as preserved, and obtuse at the posterior end. The nature of the interclavicle can not be determined.

The vertebral column is represented by a line which Cope suggests (123) may be the chorda dorsalis (notochord). Osseous vertebræ were probably present, but their nature is obscured by the carbonaceous matter covering them.

The ribs as preserved are long and curved. They are slender and attenuated at the distal ends. They were probably single-headed, but whether their articulation was intercentral or not can not be determined.

The other specimens which are referred to this species show nothing of importance in the way of structure. They consist for the most part of fragments which may or may not represent the species.

The species differs from the type of the genus (_T. punctulatus_) in the possession of a broadly rounded muzzle. This character will also separate it from other species of the genus. The sculpturing of the bones of the cranium is coarser in the present species than in the type. The form of the clavicle is different in the two species. The above-described species seems to be more closely allied to the form described as Tuditanus walcotti than to other species of the genus. I have been unable to detect the presence of limbs, although Cope says they are present.

Measurements of the Type of Tuditanus brevirostris Cope.

mm.
Median length of skull 15
Width of skull at posterior border 18
Width of skull across orbits 11.5
Length of orbit 3
Width of orbit 2
Interorbital space 4.5
Length of clavicle 7
Width of clavicle 3
Length of longest rib preserved 9
Length of entire specimen 54

The material consists of the type specimen with counterpart and two fragments which probably are to be associated with this species. Collected by Doctor J. S. Newberry.

=Tuditanus longipes Cope.=

Cope, Trans. Amer. Phil. Soc., XV, p. 210, 1874 (Sauropleura).

Cope, Geol. Surv. Ohio, II, pt. II, 398, pl. XXVI, fig. 2, 1875.

Type: Specimen No. 1099 G, American Museum of Natural History.

Horizon and locality: Linton, Ohio, Coal Measures.

The cranium of this species is quite unknown. The only genus with which the specimen can be compared in the structure of the skeleton is _Tuditanus_. From the other species of the genus the present form differs in the presence of ventral chevron rods and the elongate character of the limbs, as well as in the possession of large iliac bones, which, in the only other species in which the ilia are known, are small and slender. It seems best to locate the species in this genus for the present, although it may eventually have to be removed to another group. Very little is known of the main portion of the skeleton of the species of _Tuditanus_, other than in _T. longipes_, so an exact comparison is impossible. From all the species of Tuditanus thus far known the present species differs in the elongate character of the limbs and in the presence of ventral scutellation. There are three other species of Tuditanus in which the limbs are known. These are: _T. walcotti_ Moodie, _T. minimus_ Moodie, and _T. punctulatus_ Cope. In these three species the limbs are short and weakly developed. From the other species of _Tuditanus_ the present species maybe separated by its size principally, since nothing of the bodies of the other species is known.

The body of the present species is elongate and slender, with a long neck and probably a long tail. Ribs, as preserved, are 19 to 22, though there may possibly have been more. They are moderately curved backwards, have intercentral articulation, are attenuated at the distal extremity, and are single-headed. The anterior ribs are stouter, with a widened upper portion and attenuated distal part. The posterior ribs are more slender.

There are evidences of 28 vertebræ present. All regions of the vertebral column are present and the dorsal region is preserved entire. The cervical series is represented by the posterior vertebræ only. These are very indistinctly preserved. The dorsal vertebræ are elongate and were probably amphicœlous, although this has not been definitely determined. They are expanded at each end, thus ending in a slightly raised rim. The single-headed ribs articulate between the vertebræ. The exact number of the dorsal series can not be ascertained, although this may have been 25. The spines of the vertebræ are not determinable, since the animal is preserved on its back. The caudal vertebræ are represented by two patches of the remains of what was once probably the entire series. Cope ascribes 70 mm. to the tail, but I do not find that much. The specimen may have been mutilated since he studied it. The caudals are slender and, like the dorsals, are expanded at the extremities.

The scapular arch is not preserved, but the pelvic arch is represented by the two iliac bones in good state of preservation. These are short, flat bones expanded at the anterior extremity, as preserved. They lie turned a little to each side of the vertebral column and partially obscure the femora. The iliac bones are quite characteristic of this form, since similar-shaped elements have not been observed in any of the other Carboniferous forms from the same deposit.

The greater part of the forelimb is preserved, although much of the hand is missing. The humerus is an unusually elongate bone and lies somewhat across the vertebral column. It is crushed flat and the ends are partly destroyed. It shows evidences of expansion at the ends, although not a great deal. It is much longer than the radius and ulna, which are of about equal length. The ulna is larger than the radius and has expanded ends, with the upper end more expanded than the lower and both ends slightly truncate. The radius is a simple rod of bone and is but slightly expanded. The carpus was evidently cartilaginous, since there is no evidence of osseous material in its place. There is but one phalangeal bone preserved, and, since this is displaced with reference to the ulna and radius, its position can not be determined. It may have been a metacarpal. It is short and expanded at the ends.

The hind limbs are represented by the two femora and the upper portion of the tibia. The femur is almost as elongate as the humerus and is more slender. It is not so much expanded as the humerus. Its ends appear to have been cartilaginous and do not represent the well-formed articular surfaces preserved in the _T. minimus_. The upper part of the tibia is preserved, and appears to have been truncate.

If this species belongs with _Tuditanus_ it is of interest in that the ventral chevrons are present. The species is particularly characterized by the elongate limbs.

Measurements of the Type of Tuditanus longipes Cope.

mm.
Length of vertebral column between pelvis and
end of humerus 7
Length of vertebral column anterior to humerus 18
Length of caudals present 42
Length of humerus 19
Width of humerus 2
Length of radius and ulna 12
Length of a vertebra 3
Length of ilium 7
Length of femur, estimated 18
7 chevrons in 4 mm.

=Tuditanus minimus Moodie.=

Moodie, Jour. Geol., XVII, No. 1, p. 56, fig. 10, 1909.

Moodie, Proc. U. S. Nat. Mus., 37, p. 23, pl. 8, fig. 2, 1909.

Type: Specimen No. 4555, U. S. National Museum.

Horizon and locality: Cannelton slates of Pennsylvania (Upper Freeport).

The species is represented by a nearly complete skeleton preserved on a slab of slate from the Cannelton shales of Pennsylvania. The obverse slab has been lost, which is very unfortunate, since there is no doubt that the entire skeleton was originally present. The species is placed in the genus Tuditanus on account of the close resemblance to the type form _T. punctulatus_ Cope, although it is much smaller than that species.

The type specimen of the species did not attain a length of more than 3.5 inches. Its form is very lizard-like, but its structure is typically amphibian. The form of the skull is especially similar to that of the type species _T. punctulatus_, which it resembles in the narrow posterior truncation of the skull, as well as in the anterior position of the orbits.

The skull is in the form of a narrow oval, sharply narrowed posteriorly and truncate. The orbits are located well forward and their posterior border lies in front of the line dividing the skull transversely into equal parts. The interorbital space is greater than the diameter of the orbit. Impressions of teeth are preserved on the premaxillæ and maxillæ; there are 8 of them in a distance of 3 mm. The teeth appear to be mere blunt denticles and were possibly pleurodont.

The elements of the cranium are very poorly preserved. It has been impossible to determine all of the sutures. The bones of the premaxillary region have been destroyed, but the arrangement of them was probably not far different from that which obtains in other members of the genus. The posterior boundaries of the nasals are preserved and prove this element to have had an obtuse posterior border. The sutures bounding the frontals are clear and show that they were small and that they formed a part of the inner boundary of the orbits. The parietal is recognized as a large element, apparently the largest in the skull. Together the parietals form a wide oval inclosing, on the median suture, the circular pineal foramen. The parietals are sculptured with coarse radiating grooves and ridges, much after the manner of _Erpetosaurus radiatus_ Cope. The pittings present on that form are, however, absent in _T. minimus_. The sutures bounding the postparietal are tolerably well defined and these show that element to have been rather large and quadrate, with the usual relations. The tabulare is distinct, triangular, and small. It is produced into an angle on the posterior border strongly recalling a similar condition in _T. punctulatus_. The boundaries of the prefrontals and the upper borders of the maxillæ are not clearly ascertained. The lacrimal has not been detected. The post-frontal and postorbital form the posterior boundary of the orbit, although all of the limits of the latter element have not been definitely determined. The position of the supratemporal is well assured, although its entire boundaries are not determined. It has the usual relations and joins the parietal broadly. The jugal is broad and widens posteriorly to join the squamosal, which, as usual, forms the quadrate angle of the skull. The sutures bounding the quadratojugal and the posterior end of the maxilla are not determined.

There are but two fragmentary vertebræ preserved and an estimate based on the length of these remains gives about 30 presacral vertebræ. The structure of the vertebræ preserved can not be ascertained, but the neural spines appear to have been low and stout.

There are six elements of the pectoral girdle preserved. These are: the six clavicles, the interclavicle, the coracoid of one side, and the two scapulæ. The interclavicle is rhomboid in form and acuminate posteriorly. It is sculptured with radiating grooves and ridges. It is quite different from the same element in _T. punctulatus_, in that the base is acuminate, not truncate. The clavicle presents much the same shape as does that element in _Erpetosaurus tabulatus_. It is ornamented by a sculpturing of radiating lines which take their origin from the lower external angle as the bone lies in the matrix. The clavicle is somewhat triangular in shape and lies close to the skull, but this close approximation of the pectoral elements to the cranium is due probably to post-mortem shifting, since the scapulæ are shifted backward. There can be little doubt, however, that the pectoral arch was close to the cranium. There is an oval fragment preserved on the left of the specimen which I take to be a portion of the coracoid. The scapula is preserved entire on the left side and is represented by fragments on the right side. It is almost semicircular in form and narrows externally until it is somewhat fan-shaped. There appears to be an ornamentation of lines on the surface of the bone. These lines follow the contour of the anterior border.

The arm is preserved nearly complete on the left side, and the right side shows the humerus and the forearm. The humeri are unusual in having well-developed articular ends as though the endochondral tissue was well developed. The humerus is expanded at the ends and it is larger at the upper than at the lower end. The ulna is expanded at the proximal extremity, but is more attenuated at the distal portion. It is shorter than the humerus by about one-third of its own length. The radius is a mere slender rod of bone and presents well-developed articular ends. It is slightly shorter than the ulna. The carpus is unossified and its position is represented by a blank space. There are phalanges of 4 digits preserved and they are 4 in number. The phalangeal elements, like the other bones of the extremity, have the articular surfaces prominent, with the terminal phalanx claw-like.

There are no ribs nor traces of them preserved, and a conjecture as to their character can not be hazarded, since they are known in but two other species, in which they are slender and curved. There is no evidence of a ventral scutellation, and so far as is at present known this structure is absent from all of the species of the genus, or at least it is weakly developed.

The ilium is all that is preserved of the pelvis. The bone itself has disappeared and has left a depression which shows this element to have been an elongate rod very similar to that described for _Micrerpeton_. The sacral vertebra seems to be indicated by a depression between the iliac depressions.

One hind limb is preserved nearly entire and the greater part of the other is also preserved, although some of the phalanges are disturbed. The femur is slender and more elongate than the humerus. It has well-formed, rounded, articular ends. The tibia presents unusual characters in that its ends are truncate, as though the cartilage composing its articular surfaces was not so highly calcified as in the other limb bones. It is somewhat expanded at the ends and is throughout its length broader than the femur. The fibula, like the tibia, is a slender rod of bone, although it is somewhat shorter than the tibia. The tarsus is unossified and its position is occupied by a blank space. Portions of both feet are preserved, but only one digit in the right foot is complete. The metatarsals are elongate and slightly expanded at the ends. There are 4 phalanges present in the complete digit, which possibly represents the fourth. The first digit is wanting, with the only terminal phalanx preserved claw-like.

Measurements of the Type of Tuditanus minimus Moodie.

mm.
Median length of skull 15
Width of skull at posterior border 16
Length of orbit 3.5
Width of orbit 2
Interorbital width 2.5
Length of clavicle 6
Width of clavicle, maximum 3.5
Length of interclavicle, estimated 5
Width of interclavicle 3.5
Length of scapula 3.5
Width of scapula, maximum 2.5
Length of coracoid (?) 2
Length of humerus 4
Length of radius and ulna 3
Length of metacarpal 1
Length of ilium 2.5
Length of femur 4.5
Length of tibia and fibula 3
Length of foot 3.5
Length of metatarsal .75

=Tuditanus walcotti Moodie.=

Moodie, Proc. U. S. Nat. Mus., XXXVII, p. 16, pl. 6, figs. 1, 2; pl.
7; 1909.

Type: Specimen No. 4474, U. S. National Museum.

Horizon and locality: Linton, Ohio, Coal Measures.

A small species of Microsauria is preserved as a smooth impression on a block of soft coal from Linton, Ohio. Nearly the entire form of the body is discernible. The specimen is especially interesting and valuable as exhibiting for the first time among the Linton forms the shape of the body of the small microsaurians of the Tuditanus type. It differs so markedly in the form of the skull from other species of the genus that it is regarded as a distinct form, and the name _Tuditanus walcotti_ was proposed for it as an expression of the writer's indebtedness to the Secretary of the Smithsonian Institution for the vise of the material among which the present form was included.

B. Left leg of second specimen of Tuditanus walcotti. × 3.]

The specimen includes, besides the body impression, the complete skull, a right clavicle, with portions of the left, a left humerus, 12 cervical and dorsal vertebræ, 10 pairs of ribs somewhat disturbed as to position, and a portion of the mandible. There are no traces of ventral scutellæ nor body scales in the smooth impression of the carbonized skin. One would expect to find impressions of the ventral scutæ in this specimen if they were present. Cope remarked on the apparent absence of scutellæ from members of the genus _Tuditanus_ as they were known to him, and no contrary evidence has since been brought to light. Until such evidence is forthcoming the absence of scutes will be taken as one of the generic characters of the genus _Tuditanus_. Under a magnification of 50 diameters the carbonized skin shows as folds and wrinkles, like muscle fibers, in some places; in others no traces of the muscular structure can be detected. The wrinkles may be impressions of the internal musculature of the body-wall of the abdomen. It is especially well preserved in the pelvic and pygal regions. Sections of the coal were made, but nothing definite could be determined as to the character of the impressions, as they were too poorly preserved and the coal was too soft to bear much handling.

The specimen is preserved on the belly, with the dorsum of the skull uppermost. It has been practically impossible to determine the arrangement of any of the cranial elements except the f rentals, parietals, and postparietals, which have the relations indicated in figure 21, A. A median suture is clearly evident, with the pineal foramen well back in this suture. The bones of the skull are marked with faint radiating lines. It is in the form of the skull and the position of the orbits that the specific characters are found, as follows: the backward position of the eyes and the oval, pointed shape of the skull. The species is closely related to _Tuditanus minimus_ Moodie, from the Cannelton slates of Pennsylvania, and serves further to connect the forms from the Ohio and Pennsylvania localities. It differs from the last-named species in the position and form of the orbits, these structures being more oval in the present form and placed further back. The shape of the skull differs also in the almost entire absence of the posterior table. The median points of the orbits occupy the line which bisects the skull, and the interorbital width is less than the width of the orbit. The mandible is heavy and appears to have borne sharp, pleurodont teeth.

The vertebral column is represented by little more than a mold of the form of the vertebræ, so that little can be said of its character. The individual vertebræ are short and hour-glass-shaped. The ribs are borne intercentrally, as in all the microsaurians which have been studied from the Linton deposits. The ribs are rather long and somewhat heavy, slightly curved and expanded at the proximal end, as though an incipient bicipital condition were present.

The right clavicle, which is preserved as an impression, is entire. Its impression shows this element to have been ornamented on its ventral surface with radiating grooves and ridges which started at the lower angle of the bone. The element is distinctly triangular, which is characteristic of the genus _Tuditanus_, so far as known. The fragment of the left clavicle adds nothing to our knowledge of the element.

The left humerus recalls in a striking way that of _Tuditanus longipes_ Cope, and it was once entertained as a possibility that the present form might be a member of that species, since the skull is lacking in _T. longipes_. Sufficient specific differences were found, however, in the ribs, which, in _T. longipes_, are very long, slightly curved, and delicate, but which, in the present form, are comparatively heavy. Other characters sufficiently diagnostic are found in the form assumed by the vertebræ in the two forms.

Measurements of the Type of Tuditanus walcotti Moodie.

mm.
Length of specimen 70
Length of skull 20
Posterior width of skull 14
Width of skull, anterior to orbits 10
Length of orbit 4
Width of orbit 2
Interorbital width 3
Length of clavicle 9
Greatest width of clavicle 4
Length of vertebral column, as preserved 50
Length of a vertebra 1.75
Width of a vertebra 50
Width of body impression 15
Length of humerus 6
Median width of humerus 50
Width at end of humerus 2
Length of rib 8
Width of rib 25

The above-described specimen was collected by Mr. R. D. Lacoe, of Pittston, Pennsylvania, from Linton, Ohio.

A second individual (No. 4481, U. S. National Museum) of this species is indicated by a rather poorly preserved specimen on a slab of soft coal from the Linton mines. The following portions of the animal have been detected and will be discussed: partial impression of the skull, with a fragment of a minute jaw, in which are minute teeth; right clavicle; part of the impression of the body; nearly entire left hind limb; impressions of about a dozen vertebræ, very indistinct.

The impression of the skull is distinct only in a favorable light, and even then the boundaries of the cranium are a little uncertain. For this reason no representation of the form will be attempted. The sculpturing on the parietals is, however, distinct enough to show relationship with the previously described specimen, and the form of the body impression, the absence of abdominal scutes, the shape of the clavicle and its sculpture, and the proportions of the hind limbs all agree with the characters which have been assigned to the genus _Tuditanus_. The fragment of the jaw is interesting as giving the first information as to the character of the mandible in the genus _Tuditanus_. It is very slender and of uniform width as far as preserved. The teeth are short, blunt cones, apparently pleurodont.

The clavicle is of the typical _Tuditanus_ form, with the sculpturing lines radiating out from the angle. The impression of the body adds nothing to that already described for the type specimen. The nearly entire hind limb is of great interest as adding another example of the phalangeal formula. The foot is almost perfectly preserved, and the formula was probably 2-2-3-3-2. The endochondrium of the limb bones is not highly developed. About a dozen vertebræ are represented by molds in the soft coal, but nothing of their structure can be determined.

The sharp, reptile-like claws in which the toes end (fig. 21, B) recall those of _Eosauravus_ and of _Tuditanus minimus_ Moodie. It is another link in the chain of the suggested relationship between the microsaurians and the early reptiles.

Measurements of the Second Specimen of Tuditanus walcotti Moodie.

mm.
Length of entire body impression 75
Width across belly, maximum 16
Length of skull ?17
Posterior width of skull ?14
Length of fragment of jaw 4
Width of fragment of jaw 1.5
Length of tooth in jaw .25
Length of clavicle 8
Width of clavicle, maximum 4
Length of hind limb 22
Length of femur 8
Length of tibia (?) 6
Length of metatarsal 2
Length of first digit 6

=Genus ERPETOSAURUS Moodie, 1909.=

Moodie, Bull. Amer. Mus. Nat. Hist., XXVI, p. 348, fig. 1, 1909.

Moodie, Proc. U. S. Nat. Mus., 37, p. 21, 1909.

Type: _Erpetosaurus radiatus_ Cope.

Skull stout, elements sculptured with radiating grooves, ridges, and pits; orbits large and usually placed far forward; occiput sometimes with posterior table; skull more or less rounded; lateral-line canals consisting of supraorbital, suborbital, jugal, and temporal canals, the last two uniting to form a circular canal in one species; clavicle triangular, sculptured like the skull.

Our knowledge of the genus is confined to the skull. The genus was established for certain members of the genus Tuditanus and other forms which have been recently described. The species of the genus are: _E. radiatus_ Cope type, _E. tabulatus_ Cope, _E. tuberculatus_ Moodie, _E. obtusus_ Cope, _E. minutus_ Moodie, _E. acutirostris_ Moodie, _E. sculptilis_ Moodie. All of the species are from the Linton, Ohio, Coal Measures, with the exception of _E. sculptilis_ and _E. minutus_, which are from the Cannelton, Pennsylvania, slates.

The position of the genus as to family is a little uncertain, since family characters are not yet well understood among the Carboniferous forms on account of the lack of information as to the structure of the animals. If we take the absence of the ventral scutellæ as a family character, the genus will be in the family Tuditanidæ, but the evidence on this point is negative. For the present we may place the genus only provisionally in the family Tuditanidæ. The arrangement will undoubtedly require revision later.

=Erpetosaurus radiatus Cope, 1874.=

Cope, Trans. Amer. Phil. Soc., XV, p. 273, 1874.

Cope, Geol. Surv. Ohio, II, pt. II, pp. 394-395, pl. xxvii, fig. 1;
pl. xxxiv, fig. 3; text-fig. 10, 1875.

Moodie, Bull. Amer. Mus. Nat. Hist., XXVI, p. 348, pl. lxii, fig. 1,
1909.

Type: Specimen No. 8600 G, American Museum of Natural History. Locality and horizon: Linton, Ohio, Coal Measures. (Plate 25, fig. 1.) Cope originally described this species from a portion of a skull. He (123) characterized the form as follows:

"The marked character of this form is seen in the very anterior
position of the orbits and the contraction of the muzzle. The orbits
are large and are separated by a little more than their own diameter;
their posterior border is in front of a line measuring the anterior
third of the length to the supraoccipital crest, and nearly to the
line marking the fourth of the length to the quadrate region. The
posterior outline of the skull is deeply concave, the quadrate angle
projecting beyond the occipital condyles."

The base of the specimen is broken and there is no place for the occipital condyles. Unless the specimen has been mutilated since Cope studied it, the occipital condyles are not present.

The restoration of the skull given in figure 22, B varies but little from that given by Cope in 1875. The elements are practically as he represented them.

The premaxillæ are small and lie in the usual relations to the other elements. Minute conical teeth are present as impressions. They are quite similar to the teeth found in other Microsauria. The nasals are nearly square and form the inner boundary of the somewhat oval nostril, which is represented by a depression in the coal. The frontal is elongate. It is about twice as long as wide. It forms a portion of the inner border of the orbit, the remainder being made up by the prefrontals and the postfrontal. The parietals are the largest elements of the skull, but they do not greatly exceed the jugals. Together the parietals form a somewhat obtuse oval in the median region of the skull and they contain between them, in their posterior third, the small circular pineal foramen. The postparietal forms the posterior boundary of the skull. The pref rental forms the anterior border of the orbit and is triangular in shape. The lacrimal is not identified. The maxilla is an elongate element the boundaries of which are uncertain, though probably somewhat as given. The postfrontal and the postorbital form the posterior boundary of the orbit, inclosing between them the anterior projection of the squamosal. The squamosal is an elongate element and is acuminate at each end. The tabulare is a large element lying lateral to the postparietal. The jugal is a very elongate element, apparently acuminate anteriorly. The quadratojugal is small and elongate. The supratemporal is definitely bounded and its limits are as indicated (fig. 22, B), being a large element which forms the quadrate angle.

There are two other specimens of this species in the collections and a fragment of a fourth which it is difficult to make out. Cope identified and figured one of these as _E. radiatus_ (Geol. Surv. Ohio, II, pt. II, pl. 34, fig. 3), but the identification is doubtful and the figure shows structures which I am unable to identify in the specimen. Nothing of importance is to be learned from the other two specimens, except that they show a diversity of size. They consist of incomplete skulls, concerning which Cope (123) remarks:

"There are no mucous canals. The sculpture consists of strong ridges
radiating and inosculating. Radiation is more uninterrupted on both
jugal, supratemporal, and anterior part of the tabulare; on the first
they originate in front of the middle exteriorly; on the supratemporal
near the anterior part. The inosculation is honeycomb-like on the
parietal, postfrontal, and posterior parts of the tabulare."

Measurement of the Type Specimen.

mm.
Length of the skull along median line (estimated) 60
Length from muzzle to quadrate angle 71
Width at posterior border 69
Width at orbits 40
Length of orbit 9
Width of orbit 8
Interorbital width 8
Length of nostrils 2

Measurements of Another Specimen of the Species.

(No. 8598 G, American Museum of Natural History.)

mm.
Median length of skull 56
Length to quadrate angle 61
Width at posterior border 50
Length of orbit 7
Width of orbit 6
Interorbital width 4.5

The specimens of this species were collected by Dr. J. S. Newberry.

Erpetosaurus obtusus Cope, 1868.

Cope, Proc. Phil. Acad. Nat. Sci., 1868, p. 213.

Cope, Trans. Amer. Phil. Soc., XIV, p. 12, fig. 1, 1869.

Cope, Geol. Surv. Ohio, II, pt. II, p. 396, fig. 11, 1875.

Cope, Proc. Amer. Phil. Soc., 1885, XXII, p. 407 (Pal. Bull. 40).

Moodie, Bull. Amer. Mus. Nat. Hist., XXVI, p. 350, pl. lx, fig. 2.

Type: Specimen No. 8601 G, American Museum of Natural History.

Horizon and locality: Linton, Ohio, Coal Measures.

The species, _Tuditanus obtusus_, was first described by Professor Cope as _Dendrerpeton obtusum_, but he subsequently referred the species to the genus _Tuditanus_. It was removed by the writer to the genus _Erpetosaurus_ in 1909. The species is known from two partially preserved crania. The skull elements seem to have disappeared and left only the impressions. The sutures are, for the most part, clearly represented, but the skull shows no sculpturing. On the posterior third of one cranium there is a small space which seems to be slightly sculptured, as Cope indicated in his drawing. The general form of the skull is that of a broad oval, truncate posteriorly. The orbits lie in the anterior third of the skull, and the pineal foramen in the posterior third. Cope compared the skull to that of Huxley's _Erpetocephalus_, to which it has some resemblance. The nostrils are elongate and are situated at an obtuse angle with relation to the main axis of the skull.

The premaxilla is small and forms the inner border of the nostril. There seem to be impressions of small teeth, but no large ones are evident. The nasals are separated by a zigzag suture, and are nearly square. They have the usual relations. The frontals form a portion of the inner boundary of the orbits and unite behind with the parietals, the anterior extensions of which they inclose. The parietals are large elements and together form a broad oval, truncate posteriorly. They inclose between them the pineal foramen in the median suture. It lies in the posterior fourth of the parietals. The postparietals are elongate transversely, and have the usual relations. The pref rental is somewhat triangular and forms the anterior boundary of the orbit. The lacrimal has not been detected. The maxilla is elongate, and with the quadrate jugal forms the exterior border of the cranium. No teeth are observed on the maxilla. The postfrontal and the postorbital form the posterior border of the orbit, and between them inclose the anterior extension of the squamosal. The supratemporal is pointed anteriorly and has the usual relations of that element, joining the postorbital, the postfrontal, the parietal, the tabulare, and the squamosal. The tabulare is larger than the postparietal and is acuminate, the point being inclosed by the squamosal and the supratemporal. The jugal widens fan-shaped posteriorly. It forms a portion of the border of the orbit. The supratemporal, as usual, forms the quadrate angle of the skull. In front of it lies the elongate quadrate jugal.

A. Outline of skull and cranial elements of _Erpetosaurus minutus_
Moodie, from the Cannelton slates of Pennsylvania. Original
in U. S. National Museum. × 2. _fr_, frontal; _mx_, maxilla;
_par_, parietal; _po_, postorbital; _pp_, postparietal; =pr=,
postfrontal; _sq_, squamosal; _spt_, supratemporal; _tab_,
tabulare.

B. Outline of skull and cranial elements of _Erpetosaurus radiatus_
Cope, from the Coal Measures of Linton, Ohio; partially restored.
× 0.75. Original in American Museum of Natural History, _fr_,
frontal; _j_, jugal; _mx_, maxilla; _n_, nasal; _or_, orbit;
_par_, parietal; _pf_, postfrontal; _po_, postorbital; _pr_,
pref rental; _pp_, postparietal; _pmx_, premaxilla; _qj_,
quadratojugal; _sq_, squamosal; _spt_, supratemporal; _tab_,
tabulare.

C. Palate of _Erpetosaurus_ (_tabulatus?_), from the Coal Measures
of Linton, Ohio. × 1. American Museum of Natural History, _ex_,
exoccipital; _m_, mandible; _mx_, maxilla; _pal_, palatine; _pt_,
pterygoid; _prv_, prevomer; _pd_, parasphenoid; _x_, anterior and
posterior palatine vacuities.

D. Outline of skull and cranial elements of _Erpetosaurus
acutirostris_ Moodie, from the Coal Measures of Linton, Ohio.
Original in American Museum of Natural History. × 1. _ex_,
exoccipital; _fr_, frontal; _j_, jugal; _mx_, maxilla; _n_,
nasal; _or_, orbit; _po_, postorbital; _par_, parietal; _pp_,
postparietal; _pf_, postfrontal; _sq_, squamosal; _spt_,
supratemporal; _tab_, tabulare.

E. Outline of larger part of skeleton of _Odonterpeton triangularis_
Moodie, from the Coal Measures of Linton, Ohio. Original in U. S.
National Museum. × 4. _h_, humerus; _il_, ilium?; _v_, vertebræ,
all of which are not represented.

F. Right mandible of _Erpetosaurus tabulatus_ Cope, from the Linton,
Ohio, Coal Measures. Original in American Museum of Natural
History. × 2. _art_, articular; _cor_, coronoid; _d_, dentary;
_ang_, angular; _sa_, surangular.

G. Skull elements and lateral-line canals of _Erpetosaurus
tabulatus_ Cope, from the Coal Measures of Linton, Ohio. × 1.5.
_fr_, frontal; _j_, jugal; _jl_, jugal lateral-line canal;
_mx_, maxilla: _n_, nasal; _or_, orbit; _par_, parietal; _po_,
postorbital; _pf_, lacrimal or prefrontal; _so_, suborbital
lateral-line canal; _pp_, postparietal; _pmx_, premaxilla; _qj_,
quadratojugal; _spo_, supraorbital lateral-line canal; _sq_,
squamosal; _spt_, supratemporal; _tm_, temporal lateral-line
canal; _tab_, tabulare; _so_, supraoccipital cross-commissure of
lateral-line canal.

]

_Dendrerpeton_ is not well enough known for an exact comparison with _Erpetosaurus obtusus_, but Cope separated the latter from _Dendrerpeton_ on the position of the orbits and the broadly rounded muzzle. This species differs from the other species of the genus in the form of the cranium, as well as in the characters which separate it from _Dendrerpeton_.

Measurements of the Type of Erpetosaurus obtusus Cope.

mm.
Median length of the skull 48
Width of skull at posterior border 56
Width across orbits 37
Length of orbit 12.5
Width of orbit 7
Interorbital space 15
Diameter of nostril 1.5
Diameter of pineal foramen 1.75

Two other specimens, Nos. 8602 G and 8608 G of the American Museum, are associated in this species.

=Erpetosaurus tabulatus Cope.=

Cope, Proc. Amer. Phil. Soc., XVI, p. 577 (Tuditanus tabulatus).

Moodie, Jour. Geol., 17, p. 52, figs. 8, 9, 1909.

Moodie, Bull. Amer. Mus. Nat. Hist., XXVI, pp. 347, 351, pl. 59, fig.
2; pl. 62, fig. 2, 1909.

Type: Specimen in the Zoological Collection of Columbia University.

Horizon and locality: Linton, Ohio, Coal Measures. (Plate 25, fig. 2.)

The species is known from a single well-preserved skull and its obverse in the collection of Columbia University in New York City. I am indebted to Dr. Bashford Dean for the privilege of studying this interesting form. It is from the Linton deposits of Ohio. The remains include a nearly complete cranium and a complete clavicle of the right side. The species agrees in all essential respects with the characters of the genus _Erpetosaurus_, presenting a broad, flat head and a triangular clavicle.

_Dendrerpeton oweni_ Dawson. Above: Skull, mandible, and bones of anterior limbs. Below: Posterior limb, pelvis, and bony scales. Nearly natural size. Erect tree, South Joggins, Coal formation, Nova Scotia. Photograph by Dawson, published through the courtesy of Dr. Arthur Willey. Original specimen in the Peter Redpath Museum of McGill University.]

The cranium is wider than long, the muzzle broadly rounded. The orbits are wide ovals, and their posterior borders fall little behind the transverse line dividing the skull equally. The interorbital width equals the long diameter of the orbit. The posterior outline of the cranium is truncate in a straight transverse line between the prominent tabulare angles. The composition of the cranium is different from that of any other species of _Erpetosaurus_ in the large size of the tabulare and the fact that the supratemporal is excluded from the parietal by the extension of the postorbitals and the tabulare. This may be a generic character and entitles the species to be placed in a new genus, but it will be retained here until more of the anatomy of the species is known. The elements of the anterior part of the skull are not preserved, but they are indicated by the broken lines in the drawing (fig. 22, G). The nostrils are, however, clearly indicated as bosses of shale. There is a mere fragment of the nasal preserved posterior to the crack indicated by the transverse line in the drawing. The frontal is elongate as in other species of the genus and forms the inner border of the orbit. The parietal, as usual, is one of the larger bones of the skull roof and the pineal foramen is inclosed in the median suture by the two parietal elements. The pineal opening lies in the posterior half of the parietal. The postparietal is almost square, being slightly elongate transversely, uniting laterally with the tabulare, with which it forms the truncate table of the skull. The suture separating the tabulare from the supratemporal is clearly distinct. Although such a position for the supratemporal is unusual it is not unique, since the same character has been observed in _Diceratosaurus lævis_ Moodie, described elsewhere (p. 120) in this paper. The postfrontal is rather small and it, together with the postorbital, forms the posterior boundary of the orbit. The postorbital is truncate posteriorly and joins the tabulare broadly. The supratemporal lies posterior to the postorbital and jugal and borders the quadratojugal, which is an unusual condition, but what significance the condition has remains to be determined. Posterior to the supratemporal lies the squamosal, which forms the quadrate angle of the skull. The quadratojugal is a small element and forms part of the lateral boundary of the skull. The jugal is a large element and forms the entire lateral border of the orbit. There are no teeth preserved on the fragment of the maxilla, but there are some impressions farther forward which resemble the pleurodont denticles of the modern Amphibia.

The sculpture of the surface of the cranial bones consists of parallel ridges which are separated by grooves equal to them in width. The ridges radiate inward on the squamosals and f rentals and outward on the supratemporals. They are somewhat interrupted on the other skull elements. The right clavicle is ornamented with a sculpture of similar radiating grooves and ridges.

Cope described an atlas in connection with this skull, but I do not find it. The slender impressions to the right of the clavicle may possibly represent ribs. They are gently curved and truncate at the inner end.

A nearly complete system of lateral-line canals has been detected on this skull. The canals preserved are: the temporal, the jugal, the infraorbital, the occipital cross-commissure, and the supraorbital. These terms were used for the first time for the Amphibia by the writer (458) in a discussion of the organs and their significance in the correlation of the skull elements. The occipital cross-commissure in the present skull is represented by a row of elongate pits, such as Andrews (8) has described for _Ceraterpeton galvani_ Huxley from the Coal Measures of England. The cross-commissure is contained within the tabulare. The jugal and temporal canals form a complete ring, much as the same canals do in _Trematosaurus_. The supratemporal in _Erpetosaurus tabulatus_ Cope is excluded from the parietal by the extension of the tabulare and the postorbital, and it is to be noticed that the temporal canal has a changed position to correspond with the changed condition of the squamosal. This is of considerable interest in connection with the correlation of the supratemporal in fishes and amphibians. This subject has been fully treated in another place (458) and it will only be necessary to state here that on the basis of the lateral-line canals and their arrangement in fishes and the Amphibia the true correlation of the supratemporal elements in amphibians and fishes has been made. The temporal canal in the present specimen has, apparently, an indication of a connection with the supraorbital canal, but of this I am not sure. The jugal canal occurs on the supratemporal and quadratojugal, and it joins the infraorbital on the jugal. The infraorbital is indicated by a short portion a few millimeters long under the orbit and the remainder, _i.e._, its connection with the jugal canal, is restored (fig. 22, G). There is, nothing unusual to be observed in that portion of the infraorbital canal which is preserved. The supraorbital canal is indicated by a curved, broad, shallow groove on the inner side of each orbit. As stated above, there seems to be a connection between this canal and the temporal, but I am not sure. The primitive conditions shown in the lateral-line canals in _Erpetosaurus tabulatus_ Cope are the presence of the occipital cross-commissure and the ring-like formation of the temporal and jugal canals, which is too clearly indicated to be overlooked.

Measurements of the Type of Erpetosaurus tabulatus Cope.

mm.
Median length of skull 29
Width of skull, posterior border, estimated 37
Width between tabulare angles 18
Length of orbit 8
Width of orbit 6.5
Diameter of nostril 1
Diameter of pineal foramen 1
Length of right clavicle 13
Width of right clavicle 5.5

Mandible Provisionally Associated With Erpetosaurus tabulatus Cope.

Moodie, Bull. Amer. Mus. Nat. Hist., XXVI, pp. 351-352, pl. lix, fig.
2; pl. lxiv, fig. 3, 1909.

This specimen is preserved almost completely on a slab of soft coal. It is impossible to determine positively to what microsaurian species the mandible belongs, but it may, for the present, be associated with _Erpetosaurus tabulatus_ Cope on account of its size and the character of its sculpture. This is the first and almost the only known example of a mandible of an American microsaurian. The form of the jaw is perfectly preserved, although the condition of the articular surface can not be determined.