B ATRAC HI A. 



331 



in Puerto Rico, that this species passes its metamorphosis within the egg, and issues 

 from it fully developed, although of small size. The eggs are laid between the leaves 

 of living plants, or under leaves or stones on the ground. Sometimes the frog sets on 

 them. They are quite transparent, and in about eight days the embryo is visible. 

 The form of the embryo is much like that of a salamander, as it is elongate, and with 

 limbs of nearly equal length. Bavay saw minute branchiae, which the other observers 

 did not repoi-t. The young left the egg in about fourteen days, wearing a tail, which 

 was absorbed in a day. 



In Calyptocephalus, the cranial ossification is more extensive than in any other 

 genus of Cystignathids8, as it o^•er-arches the temporal fossa. The feet are webbed. 

 The type, C. gayi, is a rather large green species which inhabits Chili. 



The species of Ceratophrys are of toad-like form, and frequently have dermal 

 processes of the eyelids and muzzle, which give them a strange appearance. Some 

 of them have osseous plates in the integument of the back. In TelmatoUns, the 

 auditory organs are defective. The species all live at high altitudes in the Andes. 

 One of them is said to be a vegetable feeder, and to be subaquatic, searching for food 



Fig. 198. — Development of Hylodes Tnariinicensis. 



on the bottom of the elevated lake of Titicaca. The species of Pseudis are found in 

 Brazil and southwards. They belong to a section of the family where the web of the 

 hind foot extends up between the external metatarsal bones. This occurs elsewhere 

 among the true frogs, but in most other Aiiura these metatarsals are closely bound 

 together. In the P. paradoxa the metamorphosis is more protracted than in any 

 known Anuran. The larvae reach a size equal to, if not exceeding that of the adult, 

 and retain their large tail while the legs are well developed. 



The Pelobatid^ are nearly all subterranean in their habits. There are two 

 sections of the family, the one inhabiting Europe, and the other North America. In 

 the former, the sacrum is coossified with the coccygeal style, thus giving a peculiar 

 T-shaped bone. In the latter, these bones are separate, as in other Anura. Both 

 groups display a remarkable range in the degree of ossification of the skull. In the 

 lower forms there is a large fontanelle on the top of the skull; and succeeding genera 

 see this opening covered by smooth bone. In the next type, the bones of the skull 

 are covered by a rough exostosis ; then the skin is filled with this ossification, and, 

 finally (genus Oultripes of Europe) the temporal muscle is covered with a bony, 



