liATRACllTA. 



331 



in Puerto Kico, that tliis sijcch's jmsses its mc't:imorpliusis within the egg, and issues 

 from it fully develoised, 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 niueh like that of a salamander, as it is elongate, and with 

 limbs of nearly equal length. Bavay saw minute branchi;e, whieh the other observers 

 did not report. The young left the egg in about fourteen days, wearing a tail, wliich 

 was absorbed in a day. 



In Cahjptoccphalus, the cranial ossification is mure extensive than in any other 

 genus of Cystignathidte, as it over-arches the temporal fossa. The feet are webbed. 

 The type, C gaiji, is a rather large green species which inhabits Ciiili. 



The species of Ceratoplirys 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 Tdmatobius, 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 



Fk;. 198. — Development of Hi/totlcs marfinicensis. 



on the bottom of tlie 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 Anura these metatarsals are closely bound 

 together. In the P. paradoxa the metamorphosis is more jn'otracted than in any 

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

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



The PELOBATID.E are nearly all subterranean in their habits. There are two 

 sections of the family, the one inli.abiting 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 

 grou|is display a remarkal>le 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 l)y 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 Caltrijjes of Europe) the temporal muscle is covered with a bony, 



