This species has several times made its appearance in the tropical houses of Kew Gardens. It seems to have bred and vanished again.[[92]]
Calyptocephalus is remarkable for the dermal ossification of the cranium, which has assumed the greatest possible extent. It affords a curious parallelism to Triprion and other Hylidae, which are likewise Central American forms. Only two species are known; C. gayi of Chili, and C. testudiniceps of Panama. They are large, thoroughly aquatic creatures, 5 to 6 inches in length, with huge heads. The tadpoles grow to an enormous size. One specimen of C. gayi in the National Collection is more than 6 inches in length, the tail taking up more than half of the total: the spiracle lies on the left side, the vent on the right, and the hind-limbs are still half enveloped in a kind of fold of the skin.
Ceratophrys is a genus of some ten toad-like species, living in South America, from Guiana to Argentina. The generic name alludes to the peculiar modification of the eyelid, which in most species is developed into a triangular, upright, but flexible appendage. The head, in conformity with the huge mouth, is very large. The tympanum is rather indistinct, sometimes quite hidden. Several of the species have a large dorsal shield, which is produced by a thick ossification of the cutis, but is not fused with any of the vertebral processes. The male has a vocal sac. C. dorsata s. boiei of equatorial Brazil is a monster toad, reaching a length of 6 inches. The upper eyelid is transformed into a triangular horn, whence a cutaneous ridge extends all along the side of the back, meeting that of the other side above the vent. There is no osseous shield on the back. The tympanum is hidden. Ground-colours, orange or green, with sharply marked dark brown or blackish patches.
C. cornuta, in Northern Brazil, lacks the dorsal shield, but has horned eyelids and a visible tympanum. Its coloration renders it one of the most beautiful toad-like creatures known. The ground-colours are green, black and brown, with an orange-yellow stripe over the head and back. All these colours are most pleasingly blended and arranged in marbled patches or stripes radiating from various centres, as, for instance, from the eyes towards the circumference of the mouth, the slit of which they pass, the same line of the pattern being continued upon the lower jaw. The whole surface makes the impression of a gay but exquisitely harmonious carpet. The under parts are yellow, inclining to white towards the middle.
Fig. 43.–Ceratophrys ornata. Horned Toad. × ¾.
C. ornata has a dorsal shield. The tympanum is just visible, and the eyelids form only low but sharp-edged projections. This is likewise a beautiful toad, living chiefly in Uruguay, Northern Argentina, and Paraguay, where it is universally known as the "escuerzo," one of the Spanish words signifying a toad. Its size rarely surpasses 4½ inches. The ground-colours are greenish and yellow, with large dark green patches on the back, decreasing in size on the flanks.
Fig. 44.–Ceratophrys ornata. (From Nature.)
Each of these insular patches is surrounded by a narrow line of white and yellow dots, interspersed here and there with lines of rusty brown or red. The object of this elaborate carpet-like pattern is concealment. These toads–and this applies to all the species,–bury themselves half in the ground, preferably in the grass, where they are well-nigh invisible. If there is not enough green vegetation, they throw, with their feet, little lumps of earth upon their backs, the skin of which becomes at the same time more crinkled and assumes duller tones. There the creature lies, perfectly concealed, betrayed only by the metallic glittering eyes, waiting for some unfortunate creature to pass into the trap represented by the enormous mouth, which opens and shuts with lightning-rapidity and with an audible snap. They seem to live chiefly on frogs, and sometimes they turn cannibals. Two specimens were brought over to me from Buenos Aires by a friend, in a well-closed basket with moist soil at the bottom, but only one was visible on arrival. The other was inside the larger one, and could still be felt through the soft body. This same cannibal took large-sized frogs greedily, one or two for a meal, swallowing them whole and then sinking back into its lair, which it scarcely ever left, except for an occasional soaking bath in its water-pan, especially before shedding its skin. It lived for many months in the same enclosure with a pantherine toad, Bufo mauritanica, of equal bulk, until one morning I found the Moroccan half swallowed and almost lifeless in the mouth of the American, whence it was rescued with difficulty. It came round after a few hours, but never fully recovered, lingering on for weeks; the skin was changed to a lead-colour so far as it had been swallowed and partly dissolved by the gastric juices, and soon began to develop festering ulcers.