244 Illinois State Lahoratory of Natural History. 



sented in higher turtles) within, and without by the contigu- 

 ous axillary and inguinal. Head very large, with small plates 

 above. 



Chelydra serpentina, Linn. Snapping Turtle. 



Testiido serpentma, Linn. Syst. Nat., 1758, p. 199. 



Chelonura serpentina, Say, Jour. Acad. Nat. Sci., Phila., 1825, 



IV., pp. 206, 217. 

 Testudo serpentina, LeC, Ann. Lye. Nat. Hist. N. Y., 1829, III., 



p. 127. 

 Emysaura serpentina, [in part], Dum. et Bibr., Erp. Gen., 1835, 



IL, p. 350. 

 Chelonura serpentina, Holbr., N. A. Herp., 1842, I., p. 139, pi. 



23.— De Kay, Nat. Hist. N.Y., I., Zo()l. III., Eept. and Amph., 



1842, p. 8, pi. 3, fig. 6, young. — Kenn., Trans. 111. State Agr. 



Soc, 1853-54, 1., p. 591. 

 Chelydra serpentina, Agassiz, L., Contr. Nat. Hist. U. S., 1857, 1., 



p. 417; IT., pi". 4, fig. 13-16, and pi. 5, fig. 18, 19.— Davis and 



Rice, Bull. 111. State Lab. Nat. Hist., I., No. 5, 1883, p. 53; 



Bull. Chicago Acad. Sci., 1883. 



Length from two to four feet. Carapace oval in outline 

 seen from above, depressed, rounded in front, toothed behind. 

 Dorsal plates nearly equal in size; costals but little longer; 

 marginals very small. Plastron very small, leaving the greater 

 part of the ventral surface of the animal exposed. Gular 

 plates wanting; post-gulars small. Abdominals large, not 

 forming part of the bridge between the carapace and plastron. 

 Bridge narrow, covered by the axillary, inguinal, and, in great 

 part, by an elongate extra plate. Head large; snout pointed; 

 both jaws with a median tooth. Several gular tentacles. An- 

 terior legs with transverse scales in front. Soles with small 

 round scales. Posterior legs with transverse scales before and 

 with both transversely elongate and round scales on the soles. 

 Digits 4-5. Tail long, tapering, with a series of compressed 

 and elevated plates above, and beneath with a series of flat 

 paired scales. 



Blackish brown above, pale yellow beneath. Superior 

 surface of the head, eyelids, and the jaws more or less speckled 

 and lined with brown. 



Length of shell, 4.50; width, 8.50; depth, 2.50. Measure- 

 ments from small example. 



