Class 3. Aynphihia. Order 2. Anura. 



407 



(B. vulgaris) and the Katterjaok Toad {B. calamita), with a longitudinal 

 yellow stripe down the back. 



5. The Surinam Toad {Pipa amerieana), a large, flattened Amphi- 

 bian, with small eyes, no tongue, no teeth, with large webs between the 

 hind toes. With the help of the male, the fertilised eggs are placed on the 

 back of the female : a small depression forms for each egg, in which it develops, 

 and where metamorphosis takes place. S. America. 



Order 3. Gymnophiona. 



The body elongate, vermiform, and apodoiis ; the tail rudimentary, 

 eyes degenerate ; skin with ring-like 

 grooves on . the surface, often contain- 

 ing bony scales. 



The Gymnophiona (genus Cwcilia 

 and others) live in the earth in warm coun- 

 tries ; they feed on Earthworms and such 

 animals. The embryology is well known 

 only for a single species, living in the 

 Bast Indies, Epicrium glutinosum. This 

 form lays its eggs in a hole in the gi'ound, 

 coils its body round them, and does not 

 leave them until they are hatched. The 

 completely developed embryo possesses three 

 pairs of gills, similar to those of sala- 

 mander larvae, rudimentary hind limbs, and 

 a short tail, provided with a fin.* It 

 loses its gills on hatching, and betakes pig. 331 Embryo of Dpi- 



itself to the water, where it lives for some crium glutinosum, removed 

 time. f™"" ^'^ 6gg. — After Sarasin. 



Class 4. Reptilia. 



As regards external form, the body is very like that of the 

 TJrodela, but differs in the presence of a more pronounced neck. 

 The powerful tail is not sharply demarcated from the body, and is 

 often quite round in section. The limbs are generally, as in the 

 TJrodela, small, and feeble as compared with those of the two following 

 classes ; elbow and knee are turned outwards ; the tail is usually 

 still important as a locomotor organ. 



The skin is provided with a hard stratum corneum, which is shed 

 entire at certain periods (several times a year), in Snakes and some 

 Lizards ; the former draw oif the " slough " inside out, the latter 

 crawl out of it. In the majority of Lizards, however, the horny 

 layer is moulted in large pieces, in the Chelonia and Crocodilia in 



* It is very remarkable that the egg increases in size after it is laid, until the 

 diameter becomes twice as great, and the embryo weighs almost four times as much as 

 the new-laid egg. This is probably conseqvient, to a great extent, upon an absorption 

 of water, but possibly the egg also takes in a secretion from the cutaneous glands of 

 the female. 



