REPTILU. 287 



meatus ; nostrils anterior ; tongue fiesliy, depressed, and tliick. The cloaca ia 

 situated under the tail, with the orifice rounded and puckered. The male 

 organ is simple. 



Fam. 1. TestudlnidcB. The family first to be considered embraces spe- 

 cies which are exclusively terrestrial. They are known by their high-arched 

 carapace, their full ossification, the complete investment of all the toes by a 

 common skin, forming a true club-foot, on the exterior of which are to be 

 found the blunt nails. The jaAVS are naked ; the tympanum visible ; the eyes 

 lateral, with the lower eyelid higher than the upper. The tongue also is 

 papillose. The four generic forms are, Kinixys, Ho?noj)us, Pyxis, and 

 Testtido. But one of these genera, Testiido, is found in North America, 

 where it is represented by a single species, T. polyphemus, or the gopher. 

 This animal is found in Georgia and Florida, in sandy districts, where it 

 excavates holes in the ground which much impede the movements of horse- 

 men. Another species, T. elephantopus, is found in great numbers in the 

 Gallapagos Islands, were they average 601bs. in weight. They are eagerly 

 sought for by the crews of vessels, and when captured serve for fresh 

 meat, and may be kept in the hold of a ship for a year without food or 

 drink. One species, T. graca {pi. 81, jig. 40), is found in the South 

 of Europe; while T. geometrica {pi. 81, Jig. 39, and;j/. 90, jig. 13) lives in 

 the East Indies. 



Fatn. 2. Emydidce. In this family, the feet are more perfectly formed 

 than in the last, the toes being five in number and movable, most generally 

 united by a membrane or palmated. The mandibles are usually horny, 

 trenchant, and naked. The tympanum is visible, and the eyelids are of equal 

 height. The tongue, of nearly equal thickness throughout, is smooth at the 

 surface, but presenting longitudinal folds. In most species the shell is con- 

 siderably depressed. 



This extensive family presents two sub-divisions or sub-families, whose dis- 

 tinguishing features are to be found in the shape of the head, in the position 

 of the eyes, and in the manner in which the head and neck are retracted 

 within the shell. 



In the first sub-family, the Cryptoderes. the head is conical, sometimes as 

 as high as broad ; the eyes are lateral. The neck is short, thick, cylindrical, 

 invested by a loose non-adherent skin. When the head is retracted the 

 neck assumes an S shape, and both are nearly, if not entirely, concealed by 

 the anterior margin of the shell, or by the loose skin of the neck. The 

 most sti-iking anatomical difference between the two sub-families is that in 

 this the pelvis is attached to the carapace by a cartilaginous symphysis, and 

 not at all to the plastron, this permitting a certain freedom of movement ; 

 while in the second sub-family, the pelvis is immovably attached to both cara- 

 pace and plastron. 



The first genus to be referred to among the Ciyptoderes is Cistudo, 

 which includes the common land tortoise (C clausd) of the United States. 

 Here the carapace is very high and arched, while the lower shell or plas- 

 tron is divided into two pieces by a hinge, which enables them to shut 

 close against the upper shell, and thus completely to inclose the entire 



491 



