7f. PROTEANS. SIRENS. \PODA. 



Fiy. 40. 22. The MENOBRANCHUS, also have four feet ; but in 

 stead of having four toes before, and five behind, they 

 have only four throughout. 



23. The PIIOTEANS, Proteus, have but three toes in 

 front and two behind The only -species known, 

 Proteus atuininnSi (Fig. 40.) more than a foot long, and 

 only as thick as the finger, is found in the subter- 

 raneous waters of some of the caverns of Oarniole. Its 

 skin is smooth and whitish, its muzzle is elongated and 

 depressed, and its eyes are exceedingly small, and con- 

 cealed beneath the integuments. 



24. The SIRENS, have anterior extremities only, and, 

 in the elongated form of their body, resemble eels. 

 Three species are known, one of which attains three 

 feet in length, and inhabits the marshes of Carolina. 



O FAMILY OF APODA. 



25. The APODA, or CECILIA, as we have already stated, are 

 entirely without extremities, and, until lately, have been regarded 

 as Serpents ; but it has been ascertained that, in early life, they 

 have branchiae which show themselves through a hole on each 

 side of the neck. In the adult animal we find even the arches of 

 the hyoid bone, which served to sustain these organs. The body 

 is very nearly cylindrical. The skin is smooth and transversely 

 furrowed by annular wrinkles. At first sight, it appears to be 

 entirely naked ; but on dissection, we find in its thickness rows of 

 small and extremely thin scales, situate in these wrinkles. The 

 eyes which are very small, are concealed beneath the common 

 integuments, and sometimes they are entirely wanting. These 

 animals are completely apodous, that is, without feet, and their 

 skeleton, like that of serpents, has two long rows of ribs ; but 

 these bones are much too short to surround the trunk, and, on 

 the other hand, we remark, in the mode of articulation of the 

 vertebraB, and in the disposition of their jaws, many characters 

 which approximate them to the latter batrachians. 



26. These reptiles, which establish a passage between the batra- 

 chians and Ophidians, inhabit humid and shady places, dig holes 

 in the ground, and seem to feed on vegetable substances as well 

 as on worms and small insects. They are found in South America. 



The CLASS OP FISHES comes next in order. 



22. What are the characters of Batrachians of the genus Menobranchus ? 



y.3. What are the general characters of the Proteans ? 



24. What are Sirens? 



2.>. What are the general characters of the Apoda ? 



26. Where are they found? What are their habits? 



