110 



occurrence of different species in various parts of this State; (2) the 

 inaccessible places which are the haunts of most varieties of our 

 turtles, and (3) the deplorable and almost entire absence of popular 

 literature upon this subject. 



What is a Turtle ? Dr. David Starr Jordan, in his Manual of Ver- 

 tebrates, has described the turtle as being ''A reptile with the body 

 enclosed between two more or less developed bony shields, which 

 are usually covered by horny epidermal plates, but sometimes by a 

 leathery skin. Upper shield (carapace) and lower shield (plastron) 

 more or less united along the sides. Neck and tail the only flexible 

 parts of the spinal column; these, together with the legs, usually 

 retractile within the box made by the two shields. The bony part 

 of the carapace is formed by the dorsal and sacral vertebrae, and 

 the ribs co-ossified with a series of overlying bony plates, usually 

 accompanied by a marginal row. The dorsal vertebrae have their 



^a>c 



Fig. 1. A diagram of the upper shell or carapace, and under shell or plastron, 

 with index to names of the dermal plates: Carapace, (a), Vertebral plates; 

 '(b). Costal plates; (c). Marginal plates; (d), Nuchal plate; Plastron, (e). 

 Bridge; (f), Gular plates; (g), Humeral plates; (h). Pectoral plates; (i). Ab- 

 dominal plates; (j), Femoral plates; (k), Anal plates. 



ends flattened and immovably united by cartilage, and all of them, 

 except the first and last, have their neural spines flattened hori- 

 zontally so as to form the median line of plates. On either side of 

 this series is a single row of ossified dermal plates, overlying the 

 ribs and corresponding in number to the developed ribs, of which 

 there are usually 8 pairs. No true sternum; plastron consisting of 

 membrane bones, of which there are usually 9 pieces, — 4 pairs and a 

 single symmetrical median piece. The osseous plates, both above 

 and below, correspond neither in number nor position with the over- 

 lying dermal plates. 



