Chapter II: Introduction

The beaked whales belonging to the family Ziphiidæ are, with the exception of the bottle-nosed whales of the genus _Hyperoödon_, among the rarest of cetaceans. Of the three genera _Mesoplodon_, _Ziphius_, and _Berardius_, so far as I have been able to ascertain from published records, specimens representing about one hundred individuals are known, and somewhat more than one-half of these belong to the first-named genus. _Berardius_ is the rarest genus, only about fourteen specimens having been collected thus far. The U. S. National Museum contains specimens representing some twenty-five individuals of the three genera, or about one-fourth of the material at present available. Among these are six specimens of the genus _Berardius_, or nearly half of all that have been recorded thus far.

The most important addition to the knowledge of these whales made during the last quarter century was the discovery of representatives of the three genera _Mesoplodon_, _Ziphius_, and _Berardius_, at Bering Island, in the North Pacific, by Dr. Leonhard Stejneger, whereby the known range of the family was very greatly extended. Two of the forms were described by Doctor Stejneger in 1883, and the third by myself from a skull which he collected. About one-half of the material which the Museum possesses consists of that collected by Doctor Stejneger in Bering Island and that from the same locality presented by Mr. Nicholas Grebnitzki, Russian governor of the Commander Islands.

About six years ago the National Museum received information and specimens from correspondents showing that the range of the three genera found at Bering Island extends to the eastern North Pacific, one genus (_Ziphius_) having been observed at Kiska Harbor, Alaska, another (_Mesoplodon_) at Yaquina Bay, Oregon, and the third (_Berardius_) at St. George Island, Pribilof Group, Alaska, and near Cape Mendocino, California.

On the east and west coasts of the United States the only occurrences of beaked whales known to me are as follows:

EAST COAST OF THE UNITED STATES.

_Mesoplodon bidens_:
Nantucket Island, Massachusetts. 1867. Skull in the Museum of
Comparative Zoölogy, Cambridge, Massachusetts.
_Mesoplodon europæus_:
Atlantic City, New Jersey. March 28, 1889. Young male. Skeleton,
cast, photographs, and viscera in the National Museum.
North Long Branch, New Jersey. July 22, 1905. Adult female. Skull in
the Museum of Comparative Zoölogy, Cambridge, Massachusetts.
_Mesoplodon densirostris?_:
Annisquam, Massachusetts. August, 1898. Young female. Skeleton in the
Museum of the Boston Society of Natural History.
_Ziphius cavirostris_:
Charleston, South Carolina. 1865 (?). Young female. Skeleton in the
National Museum. (Type of _Z. semijunctus_.)
Barnegat City, New Jersey. October 3, 1883. Adult female. Skeleton
and cast in the National Museum.
St. Simon Island, Georgia. 1893. Male (?). Known from a photograph;
only a few bones preserved.
Newport, Rhode Island. October, 1901. Adult male. Skeleton and
photograph in the National Museum.
_Hyperoödon ampullatus_:
New York Bay, New York. 1822. Female (?). Not known to have been
preserved.
North Dennis, Massachusetts. January, 1869. Male. Skeleton in the
Museum of Comparative Zoölogy, Cambridge, Massachusetts.
Newport, Rhode Island. 1869. Female. Skull in Museum of the Academy
of Natural Sciences, Philadelphia.

WEST COAST OF THE UNITED STATES.

_Mesoplodon stejnegeri_:
Yaquina Bay, near Newport, Oregon. February 15 (?), 1904. Adult.
Skull in the National Museum.
_Ziphius cavirostris_:
Kiska Harbor, Alaska. September, 1904. Known only from photographs.
_Berardius bairdii_:
St. George Island, Pribilof Group, Alaska. June, 1903. Adult female.
Skeleton in the National Museum.
St. George Island, Pribilof Group, Alaska. June, 1903. Young male.
Skeleton in the National Museum.
Centerville Beach, near Ferndale, California. October, 1904. Adult
male. Skeleton in the National Museum.
Alaska or California (?). Skull formerly in museum of the Alaska
Commercial Company, San Francisco.
Trinidad, California. January 30, 1905. Not preserved; perhaps not
this genus.
St. George Island, Pribilof Group, Alaska. August 21, 1909. Female.
Probably not preserved. Reported by Maj. Ezra W. Clark.

DESCRIPTIONS OF SKULLS AND SKELETONS OF ZIPHIOID WHALES.

Genus MESOPLODON Gervais.

Of this genus the National Museum has four specimens; namely, (1) a skull (Cat. No. 21112, U.S.N.M.) obtained at Bering Island, North Pacific Ocean, in 1883, by Dr. L. Stejneger, and made the type of the species _M. stejnegeri_ True; (2) a skull and photographs (Cat. No. 143132, U.S.N.M.) of the same species, from Yaquina Bay, Oregon, obtained in exchange from Mr. J. G. Crawford in 1904; (3) a skeleton, cast, and photographs of a young male (Cat. No. 23346, U.S.N.M.), hitherto supposed to represent _M. bidens_, caught at Atlantic City, New Jersey, in 1889; and (4) a skeleton of an adult (Cat. No. 49880, U.S.N.M.) from the Chatham Islands, New Zealand, representing _M. grayi_.[1]

In addition to this material, I have had the privilege of examining two skulls belonging to the Museum of Comparative Zoölogy, and hitherto supposed to represent _M. bidens_, and two skeletons belonging to the American Museum of Natural History. Of these last, one is that of an adult and was purchased by the American Museum under the name of _M. layardi_, but was subsequently recognized to be a new species and was described by Mr. Andrews, under the name of _Mesoplodon bowdoini_. The other is that of a young individual, and has been labeled _M. grayi_.

As already noted by Dr. G. M. Allen,[2] only four specimens of _Mesoplodon_ have been recorded hitherto from the Atlantic coast of the United States. These are:

1. An adult, sex unknown, but probably female, 16 feet long, found at Nantucket, Massachusetts, in 1867, and recorded by Prof. L. Agassiz.[3] The skull of this individual is in the Museum of Comparative Zoölogy, Cambridge, Massachusetts.

2. A young male, 12½ feet long, captured at Atlantic City, New Jersey, March 28, 1889. The skeleton (Cat. No. 23346, U.S.N.M.) is in the National Museum.

3. A young female, 12 feet 2 inches long, stranded at Annisquam, Massachusetts, August, 1898, and recorded by the late Alpheus Hyatt.[4] The skeleton is in the museum of the Boston Society of Natural History.

4. An adult female, said by fishermen who measured it to have been 22 feet long, entangled in pound nets at North Long Branch, New Jersey, July 22, 1905, and recorded by Dr. Glover M. Allen.[5] The cranium of this individual is preserved in the Museum of Comparative Zoölogy. The rostrum and mandible, which were originally obtained, were afterwards destroyed by accident.

I have examined all this material. Writers who have had occasion to mention these four specimens thus far have referred them tacitly to _Mesoplodon bidens_ (Sowerby), but, after a careful study of them, I have ascertained that while the Nantucket specimen belongs to that species, the Atlantic City and Long Branch specimens represent _Mesoplodon europæus_ (Gervais). This is a very interesting discovery, because the latter species has been known hitherto only from a single skull, and its validity has been frequently questioned. The Annisquam specimen, as will be seen later, presents characters which appear to ally it to _M. densirostris_.

MESOPLODON BIDENS (Sowerby).

_Physeter bidens_ Sowerby, British Miscell., 1804, p. 1; Trans. Linn.
Soc. London, vol. 7, 1804, p. 310.
_Delphinus sowerbensis_ Blainville, Nouv. Dict. Hist. Nat., 2d ed.,
vol. 9, 1817, p. 177.
_Delphinus sowerbyi_ Desmarest, Mammalogie, pt. 2, 1822, p. 521.

The only specimen from the Atlantic coast of the United States which can with certainty be referred to this species is the one from Nantucket mentioned on page 3. Prof. L. Agassiz’s original notice of it is so brief that it is quoted in full below:

Professor Agassiz also brought to the notice of the Society the
discovery of a Cetacean, new to America. The skull was exhibited, and
its peculiar features pointed out. It was obtained on the coast of
Nantucket by Messrs. H. M. and S. C. Martin, of Roxbury. It belonged to
the genus _Mesoplodon_, as characterized by Gervais, and ought to be
separated from the fossil _Ziphius_, described by Cuvier. Professor
Agassiz, however, questioned whether _Mesoplodon_ was not identical
with _Delphinorhynchus_, previously described by De Blainville. The
specimen found at Nantucket measured 16 feet in length.[6]

SKULL.

The skull of this Nantucket specimen, which I have before me, is thoroughly adult. That the specimen is a female is probable from the fact that the teeth (one of which is preserved), though fully developed, are only two-thirds as broad and three-fourths as long as those of Sowerby’s specimen (the type of the species), which was an adult male.[7] The skull is 765 mm. long, and about 30 mm. are lacking from the end of the beak, so that the original length was about 795 mm. It appears to be, therefore, rather the largest skull of the species of which there is any record. The specimen itself, according to Dr. J. A. Allen, was 16 feet 3 inches long.[8] The largest European skull appears to be the one in the Edinburgh Museum, described by Sir William Turner in 1872.[9] The length of this is 749 mm. The specimen was a female, but though the skull is so large, the mesirostral cartilage was not ossified, and the individual was, therefore, probably not thoroughly adult. Two other European specimens, of which the total length was almost identical with that of the Nantucket specimen, were (1) the adult female obtained at Overstrand, England, in 1892, and recorded by Southwell and Harmer[10] (length 16 feet 2 inches, straight); (2) the adult male obtained at Brodie House, Scotland, in 1800, and recorded by Sowerby[11] (length 16 feet). The length of the skull is not given for either of these specimens. The adult male obtained at Rugsund, Norway, in 1901, and recorded by Grieg,[12] was only 15 feet 1 inch long, but some of the measurements of the skull are as large as, or even a little larger than, those of the Nantucket skull. The total length of the skull was not given, as the end of the beak was lacking.

Grieg’s figures of the Rugsund skull afford a very satisfactory basis for comparisons between that specimen and the Nantucket skull (Pl. 1, fig. 1). Both skulls show the comparatively narrow frontal region, the moderately developed tubercle anterior to the anteorbital notch, and the low maxillary ridge, which are characteristic of the species. In both skulls the anterior prolongation of the ethmoid is lanceolate and flat, but in the Rugsund skull the apex is truncated. In the latter also the posterior end of the mesirostral ossification is divided into three longitudinal sections by two lateral and somewhat divergent grooves, while in the Nantucket skull there is only a single median groove. These differences may safely be regarded as individual. Toward the distal end the surface of the ossification in the Nantucket is pitted and irregular and descends much below the level of the premaxillæ. It ends distally at the same point with the vomer. In this skull the proximal end of the premaxillæ and adjoining plate of the maxillæ are somewhat less reflexed than in the Rugsund skull. The shape of the superior margin of the supraoccipital is alike in both.

There are no well-defined differences in the relative thickness of the beak at the base or in the form and position of the visible portion of the palatines, but in the Nantucket skull the mass of the combined frontal and lachrymal anterior to the orbit is less rounded and more triangular than in the Rugsund skull. The temporal fossæ also have a postero-superior angular enlargement not seen in the latter.

In the Nantucket skull the rostral portion of the premaxillæ is high and at the distal end vertical. The superior profile is somewhat convex, and the superior free margin rounded proximally, but sharp distally. The least distance between the free margins is 10 mm.

The pterygoids are cut off from the maxillæ anteriorly by a very narrow band of the palatine, which connects with a broad band externally and a lanceolate segment internally. The inferior pterygoid ridges diverge anteriorly. The broad surface internal to them is concave. The external border of the pterygoid sinus is nearly straight. An elongated, fusiform section of the vomer is visible on the inferior surface of the beak at the middle for a distance of 158 mm., and a small lozenge-shaped section, ill defined, is visible between the pterygoids and palatines. (Pl. 4, fig. 1.)

The expanded anterior end of the malar is rhomboidal in form, with an external free margin 11 mm. long. Anteriorly it does not form part of the margin of the anteorbital notch.

The lachrymal is irregularly oblong, with an external free margin 35 mm. long and 12 mm. thick. The distance from the anteorbital notch to the anterior end of the orbit is 60 mm. (Pl. 7, fig. 1.)

The lateral free margins of the basioccipital are extended posteriorly beyond the exoccipitals, which is a character indicative of age.

The supraoccipital has a distinct median ridge, with a longitudinal depression on each side, bounded externally by a prominent convexity. (Pl. 10, fig. 1.)

MANDIBLE.

The mandible is slender, with a very elongate symphysis, which measures 237 mm. The inferior outline of the ramus is strongly concave at the middle and slightly convex posteriorly, while the symphysial portion is bent upward. The superior outline is concave both behind and before the tooth, and also immediately anterior to the coronoid process. At about the beginning of the posterior fourth the outline is convex, and the mandible at this point is nearly as deep as at the coronoid process. The superior surface of the symphysis slopes down on each side to the median line, but each half of the surface is itself nearly plane. (Pl. 11, figs. 1, 2, and 5.)

The alveolar groove anterior to the tooth is very distinct throughout and is without septa and open at the bottom. It ends distally in a rounded aperture 6 mm. in diameter, below which are several small foramina. These lead to a very large canal which occupies all the symphysial portion of the mandible, the walls being comparatively thin. Behind the tooth the alveolar groove becomes narrower gradually and disappears in a length of about 140 mm.

The mental foramen is situated in line with the anterior base of the tooth, and is confluent with a groove which extends forward for about 80 mm. A rather shallow groove runs along the inferior margin of the symphysis.

The coronoid process is erect and rounded, and is joined by a horizontal ridge anteriorly.

TEETH.

The mandibular tooth, which is shown in Pl. 2, fig. 3, is preserved on the right side only. Its dimensions are as follows: Length anteriorly in a straight line, 75 mm.; length from the apex to the posterior end of the root, straight, 60; greatest antero-posterior breadth, 28; transverse thickness, 10; height of apex above internal superior margin of jaw when tooth is in situ,[13] 22; antero-posterior length of base of exposed portion, 30; distance from anterior end to posterior end of root, 37; greatest height of the exposed dentine crown, above the cement, 14; length of the base of the dentine crown, 12.

This tooth, as already stated, is only two-thirds as broad and three-fourths as long as that of Sowerby’s Brodie House specimen (the type of the species), which was an adult male, and leads to the belief that the Nantucket specimen was a female. This is in a manner confirmed by the Rugsund specimen, which was an adult male and had teeth as large as Sowerby’s specimen. It has to be remarked, however, that in the Overstrand, England, specimen (1892), which was an adult female, the teeth did not project beyond the gums. Messrs. Southwell and Harmer say regarding it:

The jaws were apparently completely edentulous, and although it was
possible to feel through the gums a slight prominence on either side in
the position of the teeth of the male, we could not by this means
definitely satisfy ourselves with respect to this point, nor were we
able to ascertain the presence of any other rudimentary teeth in either
jaw. The evidence which exists on this subject is favourable to the
view that the female of this species is not provided with any teeth
which are large enough to pierce the gums.[14]

It is probable that the teeth in the Nantucket specimen, though quite large, did not project beyond the gums any considerable distance. The external border of the alveolar groove behind the tooth is only 20 mm. below the apex of the tooth, and it is not unlikely that the gums in a specimen of this size had nearly that thickness, so that only the tip of the tooth would project beyond them. Though the apex is acute, it has a flat abraded surface anteriorly, which, however, is but 4 mm. long. It seems probable, on the whole, that the teeth in the female may be quite large without projecting more than a few millimeters beyond the gums.

In shape the tooth of the Nantucket specimen is almost identical with that of Sowerby’s Brodie House adult male, as figured by Lankester. The dentine at the apex is more nearly white than the cement which surrounds it. The superior margin of the latter is not a plain ring, but sends upward a papilliform projection on each side. The dentine itself has two vertical grooves on each side. The root of the tooth ends very obliquely and is rugose and irregular. The cavity is closed.

Grieg remarks as follows regarding the structure of the teeth of the Rugsund specimen:

Sections and microscopic preparations of the alveolar tooth of this
whale show that its apex consists of dentine, within which is found an
inner pulp cavity 4 mm. long and 1 mm. broad. The dentine, the
structure of which agrees with that which Turner found in _Mesoplodon
bidens_ and _Mesoplodon layardi_, is yellowish white, with the
exception of the part nearest the pulp cavity, which is yellowish
brown. It seems to correspond most closely to what Ray Lankester called
osteodentine. Throughout the tooth the dentine is covered with a very
thin layer of shining white enamel. The enamel is, however, lacking on
the front of the tooth, having probably been worn away. A section
through the middle of the tooth, at right angles with the V-shaped
furrow, shows a yellowish cement layer from 3 to 5 mm. broad, which is,
however, worn away on the front of the tooth. Within the cement layer
is a white, amorphous, calcareous mass, forming a band from 1.5 to 3.5
mm. broad, which appears to correspond to Ray Lankester’s “globular
matter” and Turner’s “modified vasodentine.” The mass seems to agree
most closely with Ray Lankester’s “globular matter,” as it has “no
structure excepting an indistinct botryoidal character visible with a
low magnifying power.” The core of the tooth consists of dentine, the
inner layer of which is brownish, while the outer is rather whitish
yellow. As above mentioned, the dentine is visible on the front of the
tooth, since both the cement and the amorphous, calcareous mass are
worn away. Moreover, it is clear that on the front of the tooth the
dentine is not covered by enamel. The pulp cavity is reduced to a fine
pore. A section across the root of the tooth shows an outer yellowish
cement layer, from 2 to 5 mm. broad, while the interior of the tooth is
filled with a white, amorphous, calcareous mass, which is interspersed
with thin yellowish lamellæ of dentine. Here and there, also, thin
lamellæ are seen to extend from the outer cement layer into the white,
amorphous, calcareous mass. The dentine lamellæ appear to be identical
with what Ray Lankester calls osteodentine. No pulp cavity is visible
in the root of the tooth.[15]

The dimensions of the Nantucket skull are given in the following table in comparison with those of seven European skulls of _M. bidens_. Dimensions of the Annisquam, Massachusetts, skull are also added for purposes of comparison, although it represents another species (see p. 9).

_Dimensions of eight skulls of Mesoplodon bidens and one skull of M.
densirostris (?)._

Column headings:
_M. bidens._
B: Nantucket, Massachusetts, 1867, M.C.Z., female? adult.[a]
C: Scotland, 1872, Turner, female young.?
D: Fæø, Norway, 1895, Grieg, female? young.
E: Shetland, 1881, Turner, male adult.
F: Rugsund, Norway, 1901, Grieg, male adult.
G: Udsire, Norway, 1869, Malm, male (No. 1).
H: Vanholmen, Sweden, 1881, Malm, male (No. 2).
I: Landenæs, Norway, 1895, Grieg, male.
_M. densirostris. (?)_
J: Annisquam, Massachusetts, 1898, True, female young.

Measurements. B C D E F G H I J
mm. mm. mm. mm. mm. mm. mm. mm. mm.
Total length [b]765+ 749 620 743± ... 733 740 660 [c]622
Length of rostrum [b]483+ 489 400 ... ... 485 500 410 [c]377
Tip of beak to [bd]607+ 572 ... ... ... 582 590 517 [cd]466
end of
pterygoid
Height from 277 241 ... 254 267 272 258 235 248
vertex to
pterygoid
Breadth between [e]277 286 [f]254 267 292 293 253 [f]260 [278]
orbits
Breadth between 289 292 262 292 295 298 270 268 266
zygomatic
processes
Breadth at 184 197 170 184 193 187 170 175 [166]
maxillary
notches
Breadth of beak 42 51 38 ... ... 36 46 [g]40 38
at middle
Depth of beak at 35 ... [h]31 ... ... ... ... [h]33 51
middle
Greatest breadth 131 127 115 114 116 129 124 122 ...
of premaxillæ
proximally
Greatest breadth 107 102 [h]104 102 108 108 100 [h]76 92
of premaxillæ
in front of
anterior nares
Greatest breadth 54 ... 53 ... 53 50 50 50 39
of anterior
nares
Length of 90 ... ... ... ... ... [h]66 82
temporal fossæ
Breadth between 222 ... ... ... ... ... ... ... 208
temporal fossæ
Breadth of 50 ... ... ... 49 56 54 80 46
foramen magnum
Length of [c]651 [ij]470 543 [i]464 ... 639 640 560 ...
mandible
Length of 237 241 162 ... ... 212 220 160 ...
symphysis
Greatest depth 106 114 92 102 116 110 97 95 ...
of mandible

[a] The size of the teeth makes it quite certain that it is an adult
female.
[b] End of beak broken off about 30 mm. from tip.
[c] Right side. Add 31 mm. for breakage.
[d] In median line.
[e] At middle.
[f] Between “suprafrontal processes of max.”
[g] Grieg’s fig., p. 18, shows 44 mm.
[h] From Grieg’s fig., p. 18.
[i] “Length of ramus.” Length of mandible=699 mm.
[j] In Trans. Roy. Soc. Edinburgh, vol. 26, 1872, p. 776.

MESOPLODON DENSIROSTRIS (Blainville)?

_Delphinus densirostris_ Blainville, Nouv. Dict. Hist. Nat., 2d ed.,
vol. 9, 1817, p. 178.
_Ziphius seychellensis_ Gray, Zoöl. _Erebus and Terror_, 1846, p. 28.

The skull of the specimen from Annisquam, Mass., (Pl. 1, fig. 2) is, I regret to say, in rather poor condition. It is broken in the left orbital region, and all the bones, especially those of the beak, are warped by weathering. The proximal extremity of the left premaxilla is lacking and also the tip of the beak.

The skull is obviously that of a young animal, as all the sutures are open and the surface of the occipital condyles is pitted, owing to imperfect ossification.

Although the dimensions of the skull, with a few exceptions, agree well with those of young specimens of _M. bidens_, as shown by the foregoing table (p. 8), certain differences stand out conspicuously. The most salient of these is the depth of the beak as a whole and the depth and shape of the rostral portion of the premaxillæ. The latter portion of the premaxillæ instead of being low, with a straight inferior margin, is very high, with the inferior margin strongly convex. At the middle of the beak the premaxillæ are higher than the maxillæ on which they rest. It is true that the shape of the beak varies greatly with age in _bidens_ and other species of _Mesoplodon_, but I do not find any evidence that such a change as is here indicated takes place in _bidens_. The form of the beak and of the rostral portion of the premaxillæ is that of _M. densirostris_.

The beak is almost as broad at the base as in _bidens_, but the lateral free margin of the maxilla anterior to the anteorbital notch instead of continuing along the side of the beak nearly to the tip, as in _bidens_, ends at a point about 90 mm. in front of the line of the notch, beyond which the sides of the beak are vertical.

The margin of the maxilla immediately anterior to the anteorbital notch is a little damaged, but there was apparently no strong tubercle at this point, and the surface of the maxilla, though convex, is not raised into a distinct ridge. In a young skull, however, one would not expect to find a high ridge. The palatines are visible from above, which is not the case in _bidens_.

The maxillary foramen is situated a little in advance of the premaxillary foramen and is directed forward, and, as Dr. Glover M. Allen has pointed out, connects with a broad groove which runs forward along the triangular, horizontal portion of the maxilla at the base of the beak. The maxillæ are much broader behind the notch than in _bidens_, and the anterior end of the malar forms the bottom of the notch. The premaxillæ are noticeably constricted immediately in front of the premaxillary foramina, and the expanded portion just behind these foramina is nearly horizontal, with a low transverse ridge near the middle. The proximal end of the premaxillæ is nearly vertical. The anterior nares are noticeably small. The foramen magnum is large, with a trifoliate outline (Pl. 10, fig. 2). The palate at the proximal end presents a median ridge with a narrow groove on each side. The palatines extend as a broad band much beyond the pterygoids anteriorly. The vomer is visible below for a space of 142 mm. near the end of the beak. A very small piece is also visible at the base of the beak, between the palatines and pterygoids. The inferior surface of the pterygoids is convex on the side adjoining the lateral free margin (Pl. 4, fig. 2).

This skull is peculiar in that there is no very distinct basirostral groove and that the basirostral ridge, as already stated, extends forward only about 90 mm. Below this ridge is a shallow broad groove which narrows rapidly forward and can be traced to the extremity of the beak, where it broadens out somewhat (Pl. 7, fig. 2).

While this skull agrees in size and in many of its proportions with similar skulls of _M. bidens_, it differs from that species and agrees with _M. densirostris_ in the breadth across the anteorbital region, in the depth of the beak and its shape at the base, in the shape of the premaxillæ both distally and proximally, in the direction of the maxillary foramen, and the shape of the maxillary bone in front of the same, in the occupation of the base of the maxillary notch by the anterior end of the malar, in the absence of any distinct maxillary ridge above the notch, in the forward extension of the palatines, and in the shape of the foramen magnum.

Flower states that there is a deep basirostral groove in _M. densirostris_,[16] but neither the figure in Gervais’ Zoologie et Paleontologie Française,[17] nor that in Van Beneden and Gervais’ Ostéographie des Cétacés,[18] shows such a groove. The conformation of the base of the rostrum appears to be about the same as in the Annisquam skull.

In regard to differences between this skull and those of _M. densirostris_ it should be stated that in the latter the premaxillary foramina are situated farther apart, and that the maxillary foramina are situated considerably in advance of those of the premaxillæ instead of nearly in line with them.

The Annisquam skull approaches _M. europæus_ in several characters, but these are such as _europæus_ shares with _densirostris_. The principal ones are the breadth of the maxillæ in front of the orbits, the presence of the malar in the base of the anteorbital notch, and the convexity of a part of the inferior surface of the pterygoids.

Dr. Glover M. Allen has given an account of the exterior, skeleton, and teeth of this specimen, from which the following particulars are extracted:[19]

Regarding the Annisquam specimen no color notes were taken, but from a
few small photographs in the possession of the Boston Society of
Natural History, it appears evident that the ventral portion was of a
lighter tint, and in one of the views a few oval whitish spots are seen
on the side a trifle behind the middle portion of the body. Another
view shows the convexity of the posterior margin of the flukes at the
median point, as well as the prominent dorsal fin. The lower jaw
protruded slightly beyond the upper. Measurements of this specimen, as
noted by Professor Hyatt, are as follows: Total length, 12 feet 2
inches; from anus to bight of flukes, 3 feet 4 to 6 inches; across
flukes, 3 feet 1 inch; from tip of rostrum to angle of mouth, 1 foot 1½
inches. The gular furrows were noted as about 10 inches long and from ¼
to ½ an inch deep.

The teeth of the Annisquam specimen barely projected above the alveoli
of the jaws and are sharply mucronate. The basal portion of each,
however, is more like that of the male’s tooth [_M. europæus_] in the
slightly convex posterior outline and the forward extension of the
anterior angle. * * *

The Annisquam skeleton has 45 vertebræ. Four of the seven cervicals are
fused. The atlas, axis, and third cervical are firmly anchylosed
throughout, save for the lateral foramina for the passage of the
cervical nerves. The fourth cervical is fused to the third by the
dorsal spine on the left side and by the tip of the upper lateral
process of the same side. Its centrum, right half of the dorsal spine
(the spine is divided medially), and the remaining lateral processes
are free. * * * The epiphyses of the fourth and fifth cervical vertebræ
and the anterior epiphysis of the sixth cervical are fused to their
respective centra, but all the other epiphyses of the vertebral column
and of the pectoral limbs are free.

The Annisquam skeleton has nine dorsal vertebræ with their
corresponding pairs of ribs. * * * The sternum of this specimen
presents few points of interest. It consists of four pieces, the
anterior-most of which is largest, slightly hollowed above, and
correspondingly convex below. The three remaining pieces are nearly
flat, with a deep median notch at the anterior and posterior border of
each. The posterior piece evidently represents a fusion of the elements
of two segments, as there are articular surfaces for two pairs of ribs.

From the foregoing, it appears that the Annisquam specimen probably had one or two vertebræ less than _bidens_ or _europæus_, and that the sternum was somewhat differently shaped. The tooth, which is figured by Doctor Allen, is conical, compressed, 54 mm. long, 30 broad at the base, and resembles teeth of immature _bidens_.

Although with such scant material it is not possible to determine satisfactorily the identity of this third species of _Mesoplodon_ in the North Atlantic, represented by the Annisquam specimen, I feel convinced that that specimen does not belong to _M. bidens_ and that there is a strong probability that it belongs to _M. densirostris_. It is true that the latter species has been found hitherto only in the Indian Ocean and about Australia, but we know so little about the distribution of the ziphioid whales that, in my opinion, that circumstance by itself should not be given very great weight.

MESOPLODON EUROPÆUS (Gervais).

_Dioplodon europæus_ Gervais, Zool. et Pal. franç., 1st ed., vol. 2,
1848-1852, p. 4; 2d ed., 1859, p. 289, pl. 40, figs. 3-6.
_Dioplodon gervaisi_ Deslongchamps, Bull. Soc. Linn. Normandie, vol.
10, 1866, p. 177.
_Neoziphius europæus_ Gray, Suppl. Cat. Seals and Whales Brit. Mus.,
1871, p. 101.

This species was based on a single specimen found floating in the English Channel about seventy years ago. An account of the circumstances under which it was found was given by Eugène Deslongchamps in 1866, as follows:

The head, which forms the subject of this last note, was given to my
father some twenty-five or thirty years ago by Mr. Abel Vautier, a
merchant and armorer of our town, who died at Paris two years since.

The captain of one of Mr. Vautier’s ships, on his return from a voyage
to the colonies, saw floating on the water, at the entrance to the
English Channel, the body of a large animal entirely covered by birds
(large and small gulls, etc.), which were devouring it. The ship
approached the stray, and the captain, knowing that Mr. Abel Vautier
was greatly interested in natural objects, had the head of the cetacean
cut off, fastened it securely with a cord, and let it trail behind the
ship. When he arrived at Caën he made a present of it to Mr. Vautier.
The piece had at that time an appearance anything but agreeable. Mr.
Vautier was especially fond of beautiful objects which please the eye,
and hence he offered it to my father, saying, “You, who are an
anatomist, can make better use of this than I can.” My father was
unwilling to refuse the present, but neither he nor Mr. Vautier knew as
yet of its extreme rarity. It is in fact, up to the present time, the
only specimen which exists, and is a unique object in collections.[20]

No additional specimens have been recorded from European waters or elsewhere, and much doubt has been thrown on the validity of the species, many zoologists regarding it as an adult of the commoner species _M. bidens_. Van Beneden remarked in 1888:

The opinions of naturalists are divided as regards the identity of this
ziphioid, which is unique up to the present time. In the eyes of some
it represents an old male of the common _Mesoplodon_, in which the
tooth, instead of developing near the middle of the jaw, has developed
near the anterior extremity. This is the opinion of Doctor Fischer and
others, who think that this unique specimen represents merely an
individual modification and that consequently it should not figure in
the list of species. We do not share this opinion. It is not impossible
that this ziphioid may belong to the other hemisphere, and this would
explain why only one single individual has been captured in Europe.[21]

In view of the circumstances surrounding the discovery of the original specimen, it is of great interest to find that two of the specimens from the east coast of the United States represent the same species. As one of them is adult and the other young, the view that the type of _M. europæus_ is merely an old individual of _M. bidens_ is satisfactorily disposed of, as is also the opinion that it represents a singular individual variation.

The two American specimens which represent _europæus_ are those from North Long Branch, New Jersey (adult female; skull, lacking rostrum and mandible, in the Museum of Comparative Zoology), and from Atlantic City, New Jersey (young male; skeleton, cast and photographs in the U. S. National Museum, Cat. No. 23346).

SPECIFIC CHARACTERS.

The species _europæus_ differs from _bidens_ in the following characters, which may be regarded as diagnostic:

Size larger and pectoral limbs relatively shorter and narrower.

The expanded portion of the maxillæ and frontals broader in front of the orbit. The protuberance which projects into the anteorbital notch much larger and the ridge on the maxilla which extends backward from it much higher. Distance from inner margin of maxillary foramen to tip of protuberance much more than one-half the distance between the maxillary foramina of the two sides. Rostrum deeper at the base. Inferior surface of pterygoids more or less convex, with a ridge (in adults) running diagonally across it.

The cranial characters above enumerated are found in the type-skull, as will be seen by examining the excellent figures in Van Beneden and Gervais’ Osteography, plate 24.

In Dr. Glover M. Allen’s account of the Long Branch specimen[22] it is stated that the fishermen who measured it reported that it was 22 feet long, while none of the European specimens (some of which were certainly adults) was more than 16½ feet long. That the measurement reported by the fishermen is at least approximately correct appears from the fact that the skull is larger than that of any of the European specimens. The beak is missing, so that the total length of the skull can not be given, but the distance from the occipital condyles to the line of the maxillary notches (straight) is 312 mm., while in the largest adult among the European specimens this distance is only 260 mm., and in the thoroughly adult Nantucket specimen 282 mm.

SKULL.

The Atlantic City and Long Branch skulls also agree in numerous other details of structure in addition to the foregoing, the more important of which will now be mentioned. Unless otherwise stated, the type-skull, as shown by Van Beneden and Gervais’ figures,[23] also presents the same peculiarities in contrast with _M. bidens_.

_Dorsal aspect_ (Pl. 2, figs. 1 and 2).—The premaxillæ are more depressed immediately in front of the blowhole than in _M. bidens_, which, with the prominence of the maxillary ridges, makes this whole region appear strongly concave. The blowhole is narrower absolutely and also relatively to the breadth of the expanded proximal ends of the premaxillæ, so that while in _bidens_ the breadth of the blowhole is much more than one-third the breadth across the proximal ends of the premaxillæ, in _europæus_ it is considerably less than a third. Both premaxillæ are much constricted on the sides of the blowhole and the effect is heightened by the greater expansion of the proximal ends of the former. These ends do not fit closely against the adjoining edge of the maxillæ as in _bidens_, but leave a transverse vacuity, or trough, which is especially noticeable in the type-skull. The anterior end of the malar bone occupies the bottom of the maxillary notch and a small portion of it is visible from above, while in _bidens_ it does not extend up into the notch at all from the inferior surface and is not visible from above. The posterior margin of the maxillæ is more squared in _europæus_ than in _bidens_.

The margins of the beak, formed by the maxillæ, instead of being straight, are somewhat emarginate a little posterior to the middle of the length and somewhat convex anterior to it, which gives the contour of the beak, seen from above, a different shape from that of _bidens_. In the type-skull of _europæus_ the mesirostral ossification appears to be higher at the proximal end than the premaxillæ, and distally extends to the end of the beak. In _bidens_ it is lower than the premaxillæ and, in the Nantucket skull at least, ends anteriorly at the same point as the vomer, or, in other words, much behind the end of the beak. It would appear from the statements of Sir William Turner, Van Beneden and Gervais, Grieg, and others, that the mesirostral ossification never reaches the end of the beak in _bidens_, but it does in _grayi_, _haasti_, _densirostris_, and many fossil species, as well as in _europæus_.

_Lateral aspect_ (Pl. 8, figs. 1, 2).—The temporal fossæ are a little longer than the orbit in _europæus_, but a little shorter than the orbit in _bidens_; in the former the superior margin is flat or a little concave, rather than convex. The exoccipital extends in an angle farther forward in _europæus_, and the suture between it and the zygomatic is, in consequence, less nearly vertical than in _bidens_. The premaxillæ at the sides of the blowhole are nearly horizontal, so that their superior surface is little seen from this aspect, while in _bidens_ they slope downward, so that the whole of the superior surface is visible. The high maxillary ridge, situated behind the anteorbital notch, is very noticeable from this point of view, as it shuts off a considerable portion of the premaxillæ. The convex inferior outline of the beak and its great depth at the base are also salient peculiarities.

_Ventral aspect_ (Pl. 5, figs. 1, 2).—The anterior ends of the palatine bones are bifurcated, the inner part being the smaller. The two bones make but a narrow angle with the median line, instead of a wide one, as in _bidens_, and the surface of the maxillæ between them is strongly convex instead of flat. This convexity is narrowed at both ends, or, in other words, is fusiform in shape. No similar conformation is found in _bidens_, in which the inferior basal area of the maxillæ is flat.

In the young Atlantic City skull of _europæus_, the vomer is visible as a small, narrow, club-shaped piece, 68 mm. long. Anteriorly it joins the premaxillæ, which form a prominent ridge in the median line. On each side of this ridge is a wide and quite deep groove. As the beak is lacking in the adult North Long Branch skull, its peculiarities can not be made known. In the type-skull the form is the same as in the Atlantic City skull, but the vomer does not appear at all on the palate. In _bidens_ the shape of the inferior surface of the premaxillæ at the distal end is quite different. A very narrow groove runs parallel with and close to the median line and the whole surface external to it is more or less convex.

MANDIBLE.

The mandible of the Atlantic City specimen of _M. europæus_ resembles that of the type, as figured by Van Beneden and Gervais, in the shortness of the symphysis and in the position of the tooth, which is in advance of the posterior end of the symphysis. A number of differences, however, require consideration. (Pl. 11, figs. 3 and 6.)

In the type, the symphysis, as shown by Van Beneden and Gervais’ figure, plate 24, fig. 2_a_, is a little more than one-fifth the length of the mandible. The same relative proportion is found in the Atlantic City specimen, but, as the latter is a younger individual, one would expect the symphysis to be shorter. The figure of Van Beneden and Gervais gives the impression that in the type the end of the mandible is broken, and that, hence, the symphysis is shorter than it was originally. It will be observed that figures 2 and 2_a_ do not agree as regards the length between the tooth and the end of the jaw, figure 2_a_ showing a greater length. In figure 2, however, the jaw seems rather too long for the cranium, and if the greater length of the symphysis shown in figure 2_a_ were introduced, it would certainly be so. The explanation of this discrepancy is not readily found; but one may be allowed to think that the symphysis is not so blunt in the type as is shown in figure 2.

In the Atlantic City specimen the superior lateral free margin of the symphysis is straight, while in the type it is much elevated. This is no doubt due to difference in age and possibly in sex. The type shows three or four mental foramina, while the Atlantic City specimen has one large posterior one and seven smaller ones anterior to it.

Another peculiarity of the latter specimen is that the coronoid process is situated much in advance of the condyle, while the angle extends considerably behind it. In the type both are nearly in line with the condyle. I am unable to explain this difference.

In the Atlantic City specimen the axis of the tooth where it emerges from the alveolus is 91 mm. from the end of the jaw. The portion of the tooth above the alveolus is 11 mm. long at the base and 12 mm. high. It is conical and sharp pointed, and is inclined forward and a little outward, especially at the tip. At the alveolus the transverse breadth of the tooth is 5 mm. The much larger tooth in the type indicates that that specimen was a male.

The mandible of the Atlantic City specimen of _M. europæus_ differs from that of _M. bidens_ in the relative shortness of the symphysis, the large number of mental foramina, the more anterior position of the tooth, and the direction of the crown, which is forward instead of backward.

_Dimensions of the type and two other skulls of Mesoplodon europæus._

Column headings:
A: English Channel, type,[a] adult.
B: North Long Branch, New Jersey, female, adult.
C: Atlantic City, New Jersey, 23346 U.S.N.M., male, young.

Measurements. A B C
mm. mm. mm.
Total length 762 ([b]) 675
Length of rostrum 459 ... 427
Tip of beak to posterior end of pterygoids 561 ... 525
Height from vertex to end of pterygoids [c]292? 283 256
Breadth between orbits 327 [d]325 [d]287
Breadth between zygomatic processes 360 [e]325 302
Breadth at anteorbital notches 210 205 [f]182
Breadth of beak at middle 66 ... 60
Depth of beak at middle 54 ... 40
Greatest breadth of premaxillæ proximally 168 147 142
The same, in front of anterior nares 111 99 104
Breadth of anterior nares 51 45 42
Length of temporal fossæ 102 115 101
Breadth between temporal fossæ 228 212 208
Breadth of foramen magnum 42 34 34
Length of mandible 654 ... 565
Length of symphysis 135 ... 116
Greatest depth of mandible 120 ... 101

[a] Dimensions taken from Van Beneden and Gervais’ figures.
[b] Beak lacking. Length from occipital condyles to base of beak
(straight), 312 mm.
[c] Pterygoids broken.
[d] At middle.
[e] Estimated. One zygoma is broken.
[f] Least.

VERTEBRÆ.

The vertebral formula of three specimens of _M. bidens_ and of the Atlantic City specimen of _M. europæus_ is as follows:

M. europæus.
Atlantic City C. 7; Th. 9; L. 11; Ca. 20=47
M. bidens.
Landenæs 7; 10; 11; 19=47
Fæø 7; 9; 11; 19=46
Udsire 7; 10; 9; 20=46

Although the skeleton of _M. europæus_ appears from the foregoing formula to include one less thoracic vertebra than those of _M. bidens_, as the last pair of ribs present is as long as the preceding ones, an additional pair probably existed originally. The formula for _europæus_ would then be: C. 7, Th. 10, L. 10, Ca. 20 = 47. (Pl. 13, fig. 1.)

In the Atlantic City specimen all the epiphyses are free. The atlas and axis are anchylosed together, the third cervical is united to the axis by the centrum, and on the right side by the top of the neural arch; on the left side the arch is imperfect and free. The fourth to the seventh cervicals, inclusive, are all free. The arch is incomplete above in the fourth, fifth, and sixth, but complete in the seventh. There is a short neural spine on both sixth and seventh cervicals. The atlas has a broad, obliquely-truncated inferior lateral process, but no superior process, while the axis has both inferior and superior processes. The inferior process is twice as long as the superior process, and both are directed backward. They do not meet to form a ring. The third to the sixth cervicals, inclusive, have inferior processes only, that on the third being long and thin (but developed on the left side only). On the fourth and fifth cervicals the processes are short and small; on the sixth, long and broad, and directed downward. The centrum of the seventh cervical has a broad facet on the side, where the first rib is attached, and an inferior lateral process thicker than that of the sixth cervical, but also directed downward.

It is doubtful whether the foregoing characters of the cervical vertebræ are of any systematic importance, as there is a very large amount of individual variation among these animals in the development of the transverse processes and other details of structure. _M. bidens_, however, appears to have superior transverse processes on most of the cervicals which sometimes unite with the inferior processes to form foramina. In the specimen of _M. europæus_ under consideration there are no superior processes, except on the axis.

Metapophyses are first distinguishable on the diapophyses of the fourth thoracic vertebra, and on the seventh assume the form of conical tubercles. On the eighth and following vertebræ they are flat, and are last distinguishable on the seventh caudal vertebra. Facets for the articulation of the tubercles of the ribs occur on the diapophyses of the first to the seventh thoracic vertebræ. On the latter vertebra the first transverse process appears as a short projection on the side of the centrum. On the eighth thoracic vertebra, the transverse process is broad and flat, with the anterior margin bent upward, and is about 48 mm. long. The base of the neural arch is strongly concave externally. The transverse process of the ninth thoracic vertebra is similar to the preceding one, but broader and not bent upward anteriorly. The base of the neural arch is also concave in this vertebra. The ends of the transverse processes of the eighth and ninth vertebræ are emarginate for the articulation of the ribs. A median inferior ridge is first distinguishable on the seventh thoracic vertebra.

As far as can be learned from the descriptions of Turner, Grieg, and others, the thoracic vertebræ of _europæus_ do not present any marked differences from those of _bidens_.

The transverse processes of the lumbar vertebræ are short, broad, and flat, and somewhat curved forward. They are expanded and rounded at the free ends. The centra increase in length posteriorly, the last lumbar having the greatest length of any vertebra in the column. The neural spines increase in length from the first lumbar to the fourth, those on the remaining lumbars being subequal, but the spine on the ninth lumbar is a little longer than the others. Median inferior ridges occur on all the lumbars and are strongest at the middle of the series. The height of the centrum of the ninth lumbar is 63 mm., width 73, and length 116. The highest neural spine is 233.

As above mentioned, the first of the vertebræ counted among the lumbars may be the last thoracic vertebra, but as there is no indication of an articular facet at the end of the transverse process it is not so considered in this place.

The lumbar vertebræ in _M. bidens_ appears to be more nearly equal in length than in the present species, but are not different otherwise.

The spines of the caudal vertebræ decrease rapidly in height posteriorly, and disappear after the tenth caudal. The transverse processes resemble those of the lumbars, but are shorter. They are last distinguishable on the eighth caudal. The transverse process of the seventh caudal is perforated by a vertical foramen. Similar but much smaller foramina occur on the sides of the centra of the eighth and ninth caudals. In these vertebræ the inferior ridges are also pierced by foramina. In the fourth caudal a ridge appears on the side of the neural arch on a level with the top of the centrum, and similar ridges are found on the succeeding vertebræ as far as the ninth caudal. The last ten vertebræ are without processes or neural arches.

Sir William Turner states that the caudals of _M. bidens_ are without vertical foramina, but the figure in Van Beneden and Gervais’ Osteography (plate 22) shows them in the same position as in _M. europæus_. The inferior ridges, however, appear to be imperforate in the former species.

RIBS.

The first seven pairs of ribs have both tubercle and head. The first is nearly as long as the second, and is very broad at the proximal end. In the seventh pair the head is double, one facet of the rib articulating with the facet on the posterior margin of the centrum of the sixth thoracic vertebra and the other with the short transverse process on the side of the centrum of the seventh thoracic vertebra. The eighth and ninth pairs of ribs articulate only with the transverse processes of the eighth and ninth thoracic vertebræ, respectively. The ninth pair of ribs, as already stated, is nearly or quite as long as the eighth, from which it seems probable that a tenth short pair was present originally. There is, however, no trace of a facet for the articulation of such a rib on the end of the transverse process of what appears to be the first lumbar vertebra.

The only difference between the ribs of _M. europæus_ and those of _M. bidens_ appears to be that the first pair is much longer proportionately in the former species.

STERNUM.

The sternum presents no differences of importance from that of _M. bidens_ figured by Grieg,[24] except that the fourth and fifth segments are anchylosed together, both laterally and transversely, and that the two sides are symmetrical. (Pl. 13, fig. 2.)

PECTORAL LIMB.

The scapula of _M. europæus_ presents an entirely different appearance from that of _M. bidens_ as figured in Van Beneden and Gervais’ Osteography (plate 22). In _europæus_ the scapula is very high anteriorly, the anterior border is convex forward and the anterior crest convex backward, bounding an elongated elliptical area. The posterior margin is straight. The acromion is short, with convex margins at the base, beyond which it narrows suddenly and terminates in a straight, cylindrical process, which is strongly inclined upward. The coracoid is as long as the acromion, nearly straight and horizontal, but expanded at the end. (Pl. 13, figs. 3, 4.)

The phalangeal formula of the Atlantic City specimen of _M. europæus_ and those of three Norwegian specimens of _M. bidens_ are as follows (the metacarpals being included):

_Phalangeal formula of M. europæus and bidens._