Chapter XII: Part I: Amphibia (11)

_R. latastei_ of Lombardy and Northern Italy down to Florence is the last of these closely allied frogs. Its affinities lie with _R. iberica_ and _R. agilis_. The latter and _R. latastei_, although living side by side in the same locality, for instance near Turin, are said not to interbreed. The voice is a rapidly uttered "keck-keck-keck;" the length remains below 2½ inches. The ground colour is greyish or reddish brown with a dark brown Λ-shaped mark between the shoulders, and a few red, orange, or blackish spots on the back. The flanks are without definite dark spots. The under parts are whitish, with a strong pink tinge, especially along the middle of the throat and on the chest, the paler portions being mottled with pale grey brown.

Perhaps the least unsatisfactory way of distinguishing between _R. agilis_, _R. graeca_, and _R. latastei_ (_R. iberica_ need not be confounded with them on account of its distribution) is the size of the tympanum, and its distance from the eye. The tympanum is smallest in _R. graeca_, its diameter being about half that of the eye and from ¾ to the whole of its width distant from the eye. In _R. latastei_ the tympanum is a little larger, and about ½ to ⅔ its own width distant from the eye. _R. agilis_ has the largest tympanum, measuring about ¾ of the diameter of the eye, and the distance between the two organs amounts to only ⅓ of the size of the tympanum.

Brown land-frogs of the _R. temporaria_ group are found in most countries of nearly the whole Periarctic and Oriental regions, and by the time their races and varieties have been studied as minutely as those of Europe are now being scrutinised, the number of species will indeed be great.

_R. silvatica_ is the chief representative in North America. It closely resembles _R. agilis_, but is smaller, only 2 inches in length, {260}and possesses a pair of internal vocal sacs. Its specific name refers to its predilection for forests of oak, among the dried leaves of which it conceals itself so successfully that it is discovered with difficulty. _R. japonica_ of Eastern Asia is almost indistinguishable from this American species and from the European _R. agilis_.

_R. opisthodon_ of the Solomon Islands has the vomerine teeth in two oblique series entirely behind the level of the choanae. The general shape of this large frog is stout, the type specimen of the male measuring 78, that of the female 125 mm. = 5 inches. The upper surface of the female is covered with small, flat warts, that of the male is much smoother. The upper parts are dark brown, while the under surface is brownish white. The male has two internal vocal sacs.

This species is interesting as affording another instance of shortened development, the whole metamorphosis being gone through within the egg. Mr. Guppy, its discoverer, has supplied the following notes: "During a descent from one of the peaks of Faro Island I stopped at a stream some 400 feet above the sea, where my native boys collected from the moist crevices of the rocks close to the water a number of transparent gelatinous balls, rather smaller than a marble. Each of these balls contained a young frog, about 4 inches in length, apparently fully developed, with very long hind-legs and short fore-legs, no tail, and bearing on the sides of the body small tufts of what seemed to be branchiae. On my rupturing the ball or egg in which the little animal was doubled up the tiny frog took a marvellous leap into its existence, and disappeared before I could catch it. On reaching the ship an hour after, I found that some of the eggs which I had put in a tin had been ruptured on the way by the jolting, and the liberated frogs were leaping about with great activity. On placing some of them in an open-mouthed bottle, 8 inches long, I had to put the cover on, as they kept leaping out."

Boulenger[115] has figured and further described the eggs and young. The egg measures 6-10 mm. in diameter, and is a transparent capsule in which the young frog is coiled up in the same way as figured by Peters in _Hylodes martinicensis_; but none of the specimens, which are in an advanced stage of development, show anything of a tail. There are no gills, but on each side {261}of the abdomen are several regular transverse folds, the function of which is probably that of breathing organs, like the tail of _Hylodes_. The tip of the snout is furnished with a small conical protuberance projecting slightly through the delicate envelope of the egg, and evidently used to perforate that envelope.

_R. guppyi_, likewise an inhabitant of the Solomon Islands, is a giant among frogs. It was discovered by Mr. Guppy on the Shortland Islands. The type-specimen measures 165 mm. = 6½ inches in length! The skin of the upper parts is covered with minute warts, and forms a strong fold above the distinct, but small, tympanum. General colour dark olive brown above, dirty white below.

_R. tigrina_ is a common species of Eastern Asia, including the Malay Islands. On account of the strength of its voice, and its size, which is said to reach 7 inches, it is called the "Indian Bullfrog." Mainly aquatic, it has a strong cutaneous fringe along the outer side of the fifth toe. The skin of the back is thrown into longitudinal folds, and a strong fold marks the upper border of the tympanum. The general colour above is olive brown, with dark spots, often with a light vertebral line; the under parts are white. The male has a pair of large external vocal sacs.

_R. gracilis_ has the same distribution, but it remains much smaller, and the toes are only half, instead of fully, webbed.

_R. catesbiana_ is now the settled name of _the_ "Bullfrog" of North America, the much more appropriate name of _mugiens_ having been sacrificed to the fetish of priority. The tympanum is extraordinarily large, at least equal to the size of the eye, largest in the male. The first finger does not extend beyond the second; the toes are connected by a broad web down to the ends, and there is a small inner, but no outer, metatarsal tubercle. The upper parts are olive brown, clouded with dark brown or blackish spots; the under parts are yellowish white, often marbled with brown, especially on the throat. The iris is reddish, with an outer yellow ring. The male possesses two internal vocal sacs. Total length of adult specimens about 5 inches, but there are giants on record 7 inches in length, while the stretched hind-limbs measure another 9 or 10 inches. Its home extends over the whole of the United States, East of the {262}Rocky Mountains, southwards into Mexico, northwards into Canada.

According to Holbrook the Bullfrogs are solitary in their habits, only collecting together in the breeding season, when hundreds may be seen in the same small pond; and then the croak uttered by the males is so loud as to resemble the distant roaring of a bull, and can be heard on still evenings at a distance of half a mile. The voice is a hoarse bass "brwoom," playfully translated into "more rum." "They cannot be said to abound, but are found commonly enough sitting half immersed in water, or on the banks of ponds, waiting for their prey. If alarmed they hop suddenly into the water, but do not conceal themselves at once, frequently skimming along the surface for several yards before they dive below." They are the most aquatic of all the North American frogs, and Holbrook has known specimens to live in wells for years, where they could not rest a moment on solid ground above the water.

The Bullfrog is voracious, and takes almost anything that lives or gets into his own pond–Mollusca, Crustacea, fishes and, above all, frogs. There is no doubt that they drag down and swallow a good many ducklings and the young of other water-fowl, but certainly not the half-grown birds which have a way of disappearing from the farms wherever there are negroes and other farm-hands about. In turn the bullfrog has sufficient enemies to keep its numbers down, in fishes, birds, otters, and snakes, and, in the South, alligators. Although easily kept and growing comparatively tame, they are dull, having to be kept in solitary confinement on account of their greediness, which knows no limits. Two of our specimens each swallowed a full-grown _Salamandra maculosa_, and died within the same night, probably not understanding the meaning of the conspicuous black and yellow warning colours of the European.

_E. clamata_ s. _fontinalis_, likewise an inhabitant of Eastern North America, may be called a smaller edition of the Bullfrog, its usual full-grown size being about 3½ inches. The tympanum is conspicuously large, but the toes are webbed to a lesser extent, and the skin forms a glandular fold which extends from the shoulder in a curve to the flank. This species is partial to the neighbourhood of running streams; it is said to be {263}exceedingly timid, and to utter a short cry when disturbed and making its enormous leaps.

Another North American relation is _R. halecina_ s. _palustris_, frequenting the neighbourhood of ponds and rivers, very lively and capable of jumping 8 to 10 feet. The tympanum is smaller than the eye, but there is the same glandular lateral fold as in _R. clamata_. The vocal sacs are internal and decidedly small.

_R. esculenta._–The common Water-frog of nearly the whole Palaearctic region is closely allied to the American Water-frogs described above, and, like most of them, has the vomerine teeth in two small oblique rows between the choanae and extending a little beyond their posterior border. But the males have a pair of external vocal sacs. The tympanum is distinct, about two-thirds the size of the eye. The first finger is slightly longer than the second. The toes are entirely webbed. Besides the usual subarticular phalangeal tubercles, the sole of the foot is provided with two metatarsal tubercles, the outer of which is very small, while the inner is much larger, although varying in size from a soft oval to a long, curved, shovel-shaped structure. The skin is smooth, except for a pair of prominent glandular folds which extend from behind the eye along the dorso-lateral line. The coloration varies considerably. The upper parts are mostly greenish brown, with black brown spots on the back, and larger patches on the limbs. Most specimens have three lighter stripes along the back, the middle one mostly green, the two lateral bronzy brown and coinciding with the glandular folds. The tympanum is brown, and there is occasionally a dark temporal patch. The posterior aspect of the thighs is invariably {264}spotted with black and white or yellow, in opposition to the _R. temporaria_ group, where these parts are never spotted.

The total length of this species varies much. Specimens 2½ inches in length are certainly mature, those of 4 inches are unusually large, and Boulenger has received a giant from Damascus, which measured 125 mm., or nearly 5 inches. The females are larger than the males.

The variations in colour are not only local but also individual, moreover the colours are changeable. The ground-tint ranges from dull brown through olive to bright green, the dark spots being more or less pronounced and numerous; the light vertebral line is olive-yellowish, bright green, or altogether absent.

Those which inhabit waters with plentiful vegetation, like water-lilies and other luxuriant plants, are generally prettier and more vividly coloured than those which live in swamps and ponds with dark mud, or where the prevailing vegetation has a sombre aspect. Cold and dull, warm and sunny days also influence the water-frogs, and those which have been kept in a dark tank look very different from the bright assembly which had been put in some weeks before.

Various attempts have been made at subdividing _R. esculenta_ of Linnaeus into sub-species, and Boulenger has now, after the attentive study of an enormous material, arranged them in four principal and recognisable races. The chief differences are the relative length of the femur to the tibia and the size of the metatarsal tubercles.

1. Var. _ridibunda_, Pallas.–The right and left heels overlap each other when the thighs are stretched out at right angles to the vertebral column, and the tibia is closely folded up against the thighs. When stretched forwards, the heel reaches the eye or even the tip of the snout. The inner metatarsal tubercle is feebly developed, very small and blunt; the outer tubercle is absent.

That part of the thighs which is concealed by the legs when the animal is at rest is whitish or pale greenish, marbled with dark olive, or bronze, or of the latter colour with or without small light spots. No trace of yellow is ever to be detected on that region, nor at the axillae or on the groin. The vocal sacs are strongly pigmented with black, when inflated they are pale grey. The iris is a mixture of black and gold.

{265}This form or race has the widest distribution, namely, all over Europe with the exception of England, the northern half of France, the Rhine countries, Denmark, and Italy. Southwards it extends from France through Spain and Portugal into the Sahara, eastwards into Turkestan. It attains a larger size than the others, but only in certain localities in various countries, where circumstances favour its development. Eastern countries produce the largest of all; those of the Volga are said to be very large. German physiological laboratories prefer those from the Danube, from Bohemia, and from the lakes and broad expansions of the Spree, to specimens from other localities.

2. Var. _typica_ (_esculenta_, Linnaeus).–The heels just meet, but do not overlap. The inner metatarsal tubercle is strong, compressed, and prominent. A small outer tubercle is present. The heel reaches to the eye or a little further; the hinder surface of the thighs is "marbled with black, usually with more or less bright yellow pigment" in the living specimens; the vocal sacs are white or feebly pigmented. This race inclines to rather more green than the others, the males especially are often dark grass-green, with scarcely any markings. The vertebral stripe is then yellowish, and the lateral stripes almost golden. The range extends over the whole of Central Europe and the kingdom of Italy. Its northern limit is the southern end of Sweden. In the greater portion of Germany, Poland, and Austria it overlaps the var. _ridibunda_, with which it does not seem to pair, owing to a difference in the time of spawning; the var. _typica_ being about a fortnight later, and beginning to spawn when the other has finished.

3. Var. _lessonae_, Camerano.–Except that the inner tubercle is stronger, while the outer one is near the vanishing point, and that the fourth toe is proportionally longer, this variety is really not distinguishable from the typical form, and Boulenger himself confesses that the distinction is arbitrary. The var. _lessonae_ seems to have a rather sporadic distribution. It has been found in Piedmont and other parts of Italy, in Hungary and Transylvania, near Vienna, Halle, Upper Bavaria, on the Rhine, near Brussels, Paris, and what is of especial interest to us, in a few places in the eastern counties of England.

According to Boulenger's "Notes on the Edible Frog in England,"[116] the individuals of _R. esculenta_ which live in Foulmire {266}Fen in Cambridgeshire, near Stow Bedon, and between Thetford and Scoulton in Norfolk, and are generally supposed to have been introduced from France, belong to the Italian form of var. _lessonae_. "It used to be found in Cambridgeshire, in Foulmire Fen, where it was discovered in 1844; and Bell[117] assures us that his father, who was a native of Cambridgeshire, had noticed the presence of these frogs many years before at Whaddon and Foulmire, where they were known from their loud croak as 'Whaddon organs' and 'Dutch nightingales.' The species was afterwards rediscovered in Norfolk, between Thetford and Scoulton, where it is now still very abundant, and from inquiries made by Lord Walsingham, must have existed for the last seventy (80) years at least. These frogs belong to the var. _lessonae_, and differ widely (by the much stronger inner metatarsal tubercle) from those found in a few other places in Norfolk, which are undoubtedly the descendants of a number imported from France and Belgium in 1837, 1841, and 1842, and turned loose in the Fens at Foulden and in the neighbourhood.... Within the last ten years large numbers of all the three forms have been imported from Brussels, Berlin, and Italy, and liberated in various localities in West Surrey and Hampshire. Berlin specimens of the var. _ridibunda_ have also been introduced in Bedfordshire, and Italian ones in Oxfordshire."[118]

Leaving aside the question whether the so-called var. _lessonae_ is merely sporadically developed out of the typical form, the inquiry of the possible origin of the English specimens of the var. _lessonae_ is of special interest. Have they been introduced, as has been suggested, from Lombardy, or are they the last lingering descendants of native English frogs? The suggestion as to their Italian origin has naturally lost in value since similar specimens have been found in Belgium and near Paris; but we must remember that there existed considerable intercourse between East Anglia and the monks of Lombardy, who, to mention only one instance, came regularly to the old Priory of Chesterton, near Cambridge, in order to collect their rents. If the frogs were introduced by them for culinary purposes into various suitable localities their descendants would remain as local as they, and as the undoubtedly introduced French typical specimens actually are. On the other {267}hand, if we assume the _lessonae_ specimens to be the last living descendants of English natives, it is inconceivable why they should now be restricted to that eastern corner while there are hundreds of other suitable places in England and Wales which, if on the Continent, would be perfect paradises for Water-frogs. The same vegetation, the same insects, the same climate, and–an enormous advantage to the frogs–no storks.

These English specimens are "olive-brown or bronzy-brown above, with black spots, strongly marked on the flanks, where a light longitudinal area remains unspotted; glandular folds lighter; the sides of the head and the ground colour of the flanks are sometimes green; tympanum chestnut-brown; a pale yellow or pale green vertebral line, frequently edged with black; the dark cross-bands on the limbs usually very irregular, sometimes absent; lower surfaces more or less profusely spotted with blackish; iris golden. Length of a male from Stow Bedon, 64 mm. or 2½ inches; of a female, 78 mm. or 3 inches."[119]

4. Var. _chinensis_, Osb.–Distinguished by short glandular folds along the back, in addition to the long dorso-lateral pair. The metatarsal tubercle is large and shovel-shaped. Distribution from Corea and Japan to Siam.

All these Water-frogs are decidedly aquatic. They make short excursions on land when their homes are dried up, but as a rule they remain in the lake, pond, river, morass, or ditch in which they were born. Their favourite resorts are the broad floating leaves of water-plants, for instance water-lilies, or a prominent stone, a tussock of grass, or the banks of their homes, where they sit motionless, basking for hours in a half-erect, alert position, watching for insects and other small fry, which are secured by a jump, and then lapped up. Sunshine is sure to bring them out, and on our approach they make straight for the water, either by one tremendous leap or with quick bounds, but without the slightest hesitation or stopping on the way. With folded arms they take a header, swim, with the arms still folded, for some distance under water, and conceal themselves in the mud, between stones, or in the vegetation. We perhaps have not seen them at all, whilst their watchful eyes and keen ears have noticed our approach, and the pond might appear uninhabited if we had not heard the plumping noise. If we {268}keep quite still, and they have not been disturbed previously, one after another will wriggle out of the mud, rise slowly to the surface under cover of the plants, and, without causing a ripple, rise just enough for the prominent eyes and the nose to clear the surface. Then one scrambles partly on to a leaf, but the sight of the huge human figure strikes him as uncanny, as it certainly does not belong to the scenery, and he doubles back, the broadly-webbed feet making a little splash. But another appears, jumps on to a leaf in the middle, or at the farther end of the pond, settles down, and utters a little croak, somewhat like "ooaar," and soon the whole company appear one after another, each taking up its favourite position. After all, their observing powers cannot be very great. If we ourselves keep still we may wield a rod and fish for them. There is no need of a hook, a piece of red cloth tied to the end of the line and skimmed over the water causes a lively commotion. The new bait is noticed at once, and arouses their curiosity; several jump at it, and the one which swallows the bait can be lifted out before it has time to let go. However, this is after all poor sport; the game is too eager. When a boy I have often caught them with a noose of slender wire at the end of a long hazel rod. They do not mind the rod at all, their attention being fixed on the person; they allow the noose to be slipped over their heads, and a sudden jerk secures the captive. In this way they can be singled out individually. Old frogs are more wary and experienced than the younger members; they take up safer positions, and by their sudden plunges give the alarm.

The males are great musicians, singing for sheer enjoyment not only during the pairing time, but throughout the months of June and July. Warm moonlit nights are the favourite times {269}for the concert, which takes place in the water, beginning at sunset, and continuing until the early dawn. A few individuals here and there utter a single note, "gwarr, oo-arr," or "coarx," but these are only preliminaries. The precentor–the country-folk in North Germany firmly believe that in each pond one old male holds the dignified position of choir-master–begins with a sharp-sounding "brekeke," and this is the signal for all the others to chime in with the same notes, varied with all sorts of other sounds, bass, tenor, and alto, each performer filling its resounding vocal sacs to bursting size, and these bags then look as if they acted as floats. When there are several hundred of these sociable creatures, the din is continuous, and may be heard more than a mile off. There can be too much of this, just as there can be too many nightingales; and a well-stocked pond in the neighbourhood may become a perfect nuisance. There are accounts of servants having been employed in the Middle Ages for the sole purpose of keeping the noise down by beating the pond, throwing stones into the water, or otherwise disturbing the frogs. Sometimes more vigorous and lasting measures seem to have been taken; the monks exorcised them in order not to be disturbed in their vigils. Near the former monastery of Chorin, in the province of Brandenburg, the frogs have still the reputation of keeping very quiet on account of some powerful abbot who threatened them with awful consequences if they did not forego their concerts.

The length of life which these frogs can attain is quite unknown. They do not reach maturity until the fourth or fifth year, but this is long before they stop growing, and it is no exaggeration to say that few, if any, frogs die of old age, since they have so many enemies. The stork is their king in the fable, and his daily visits to his realm strike dire distress amongst his subjects, which soon learn to know his conspicuous white and black garb, and seek imperfect safety at the bottom of shallow ponds and ditches, not too deep for the long-legged and long-billed despot. Numbers are taken by birds of prey; snakes and tortoises hunt them up in the water, and they are good bait for pike and other voracious fishes. The specific {270}name _esculenta_ needs no comment, and this species is as much a martyr to science as the brown Grass-frog. The destroyers of tadpoles and young frogs are unlimited. In their turn the frogs themselves, especially the old ones, are very rapacious, and eat any living creature they can master,–insects, worms and snails, other frogs, especially the brown kind, and the young brood of fishes.

Recently caught Water-frogs are wild beyond description, much more so than the Grass-frog, but even they calm down after some time, learn to know their keeper, and allow him to handle them without trying to commit suicide by jumping on to, into, and down anything. However, they do not thrive well in captivity, and it is rare that they can be induced to breed, unless their enforced new home affords them ample freedom, and plenty of water and fresh air.

The Water-frogs appear in Germany rather late in the year, not before the middle of April, first the younger, then the adult members. In Southern Europe they show themselves earlier, and still further south they do not hibernate at all. The breeding season begins in Germany towards the end of May and continues well into June, the var. _ridibunda_ beginning mostly a fortnight earlier. The male clasps the female under the arms, throwing its own round her breast, the nuptial grey excrescences on his inner fingers pressing against her skin, the palms being turned outwards. The embrace does not last long, rarely extending over a few days. The eggs, to the astonishing number of 5000 to 10,000 in full-grown specimens, are expelled in several masses, which sink down and remain at the bottom. The eggs measure only 1.5 mm. and are yellowish-grey above, pale yellow below; their gelatinous cover swells to 7-8 mm. in width. The embryo escapes on the fifth or sixth day as a very small larva, in which, however, the mouth, eyes, and beginnings of the external gills are already discernible. At the age of two weeks the gills have shrunk away, the left-sided "spiracle" is completed, and the well-tailed tadpoles, olive brown above, yellowish white below, still hang with their suckers on to plants and stones, or lie at the bottom, nibbling away at any rotting animal matter or scraping off the green algae.

It may here be mentioned that small tadpoles of any kind can with advantage be used as cleaners of delicate and small {271}skeletons. The object is put into a vessel, and the tadpoles will soon nibble and rasp away all the edible portions, leaving the skeletal framework beautifully cleaned. But they require attention lest they rasp away the cartilage.

The tadpole stage lasts three to four months; but cold, absence of sunshine, and scarcity of food delay the metamorphosis well into the end of summer, or force them to hibernate in the unfinished condition. They are very gregarious, and when the tadpoles of several families combine, they make imposing shows. By the time that their hind-limbs begin to sprout, they frequently combine into large shoals, and instead of always feeding they swim about in their tens of thousands, all moving in the same direction, and making almost regular evolutions. Mill-ponds with steep banks are good places for watching these peculiar habits. The tadpoles reach a considerable size, the total length averaging 2½ inches, or some 60 mm. the tail taking up ⅔ of the whole length. Specimens which measure more than 3 inches are rare. The baby-frogs hop on land while still provided with a stumpy tail; when this is resorbed the little creature is scarcely half-an-inch long, and for the rest of the available season leads a rather more terrestrial life than ever after.

_Ex Africa semper aliquid novi!_ Quite recently Boulenger has received a consignment of Anura from the French Congo, amongst which were several new, remarkable genera, notably _Trichobatrachus_ and _Gampsosteonyx_. Both are true Ranidae. Pupil vertical, with vomerine teeth. Omosternum with a bony style. The outer metatarsals are bound together. In _Trichobatrachus robustus_ the toes are webbed, and both sexes have the flanks and corresponding portions of the thighs covered with numerous darkly pigmented, filamentous, cutaneous excrescences; these are several millimeters in length, giving the flanks and thighs a "hairy" appearance. Mr. F. F. Laidlaw has examined these structures. Their most remarkable feature is the presence in them of a great number of ordinary flask-shaped cutaneous glands, whilst such glands are scarce on the surrounding skin. They differ in no way from those seen in sections of the skin of the Common Frog. The fibrous connective tissue is dense and vascular; the pigment-cells are most plentiful at the base. Contrary to expectation no nerve-endings were found in these filaments.

{272}_Gampsosteonyx_ has free toes. The terminal joints of the digits stand out beyond the skin, and end in sharp, bony claws, like those of a cat.

SUB-FAM. 3. DENDROBATINAE.–About one dozen arboreal little frogs have been separated from the Raninae proper on account of the entire absence of teeth. This mere loss of teeth, and the geographical distribution suggest that these frogs do not form a natural group, but have been developed independently from other Ranidae, the Neotropical _Dendrobates_ from some likewise Neotropical genus like _Prostherapis_, the Malagasy _Mantella_ from an African form like _Megalixalus_.

The sacral diapophyses are cylindrical. The omo- and meta-sternum are well developed. The fingers and toes are free, their terminal phalanges are T-shaped and carry regular, round, adhesive discs. The tympanum is distinct, although sometimes, in _Dendrobates_, very small. The pupil is horizontal.

_Dendrobates._–The tongue is elongate, entire and free behind. The omosternum has a weak, semi-ossified style, but the metasternum remains cartilaginous. The males have a subgular vocal sac. Seven closely-allied species inhabit tropical America.

_D. tinctorius._–This pretty little species, scarcely 1½ inch in length, is quite smooth, varies much in coloration, and forms local races to a certain extent. Some are quite black, others are grey above, black on the sides and under parts; or they are grey with large black patches. A fourth variety is black above with several white or pink longitudinal stripes, while the under parts are grey, spotted with black. In others, again, the ground-colour is black, with white stripes and spots above, marbled below. But this enumeration does not exhaust the list, since living specimens are sometimes much more conspicuously coloured, some being black with large patches of saturated yellow on the head and back, while the limbs are orange red and black. This species has a wide range, from Panama to Ecuador and to the mouth of the Amazon. It owes its specific name to the peculiar use made by man of the strongly poisonous secretion of the tiny glands of the otherwise smooth skin. Other species are doubtless employed in the same way. The poison is mainly used for "dyeing" the green Amazon-parrots. This is done as follows:–The green and blue feathers on the head and neck, or other parts, according to the fancy of the {273}operator, are plucked out, and these places are rubbed with the poison, often simply with the living frog, certainly not with its blood, as is sometimes asserted. This operation may be repeated when the new, young feathers begin to bud. The result is that these appear yellow instead of green, and since the Brazilians, and to a certain extent the Portuguese, are rather partial to these artificially-produced freaks or "contrafeitos" as they call them, the industry is kept up. That the poison is also used for arrows has been mentioned on p. 38.

_D. trivittatus_, chiefly in Northern Brazil, has the first finger slightly longer than the second. It likewise varies considerably in its coloration, being either quite black, or spotted with white and brown, or with a whitish forehead and several white patches on the back and hind-limbs. _D. typographus_ of Central America is vermilion red, with small dark marks on the back; the legs are black.

The various species of _Dendrobates_ take remarkable care of their young. _D. braccatus_ lives in Brazil in "varzeas," _i.e._ moist but waterless places, and carries its tadpoles on its back, to which they are attached by a peculiar secretion. The same is said to be true of _D. trivittatus_, which sits down in a drying-up puddle, lets the little tadpoles, when they are only 6-7 mm. long, fasten themselves on, and conveys them to a safer locality, where the water is calculated not to evaporate before the metamorphosis is completed.

{274}_Mantella._–Both omo- and meta-sternum possess a bony style. The tongue is free and distinctly mitred or cut out behind. The skin is very granular. Several species, in Madagascar, were formerly put into the same genus as the American forms, until Boulenger established the genus _Mantella_ for them. The coloration is strikingly pretty. _M. madagascariensis_ is a rare instance of difference in colour between the two sexes. The male is bluish black, with light blue spots on the belly, while the thighs and the inner sides of the legs are beautifully red. The female is deep black, with a light green spot at the base and in front of the limbs; the rest is coloured like the male.

_Cardioglossa gracilis_, quite recently discovered at the Gaboon, has likewise to be added to the Dendrobatinae, on account of the absence of teeth. It is a small, slender, arboreal frog, bearing an unmistakable resemblance to the other genera by its general appearance and conspicuous, contrasting coloration of black and white.