968 17. KINOSTERNIDZ 
Cinosternum sonoriense Cope, Bull. U. S. Nat. Mus., No. 1, 1875, p. 525 
Coves, Surv. W. rooth Merid., Vol. V, 1875, p. 589; True, Bull. 
U.S. Nat. Mus., No. 24, 1883, p. 31; Boutencer, Cat. Chelonians 
Brit. Mus., 1889, p. 40; S1eBENRocK, SB. Akad. Wiss. Wien, Vol. 
116, 1907, p. $71; SteEBENROCK, Zool. Jahrb., Suppl. 10, Heft 3, 
1909, Pp. 444. 
Cinosternum flavescens Core, Bull. U. S. Nat. Mus., No. 1, 1875, p. §2 
(part); True, Bull. U.S. Nat. Mus., No. 24, 1883, p. 31 (part). 
Aromochelys carinatus YARRow, Surv. W. tooth Merid., Vol. V, 1875, 
p- 582. 
Kinosternon sonoriense STEJNEGER, Proc. U. S. Nat. Mus., Vol. 25, 1902, 
p- 149; Ruruven, Bull. Amer. Mus. Nat. Hist., Vol. 23, 1907, 
p- 594; Van DensurcH & Srevin, Proc. Cal. Acad. Sci., Ser. 4, 
Vol. 3, 1913, p- 396; GRINNELL & Camp, Univ. Cal. Publ. Zool., 
Vol. 17, No. 10, 1917, p. 200; SreyNEGER & Barsour, Check List 
N. Amer. Amph. Rept., 1917, p. 112. 
Description —Shell rather narrow, elongate, somewhat 
depressed, smooth. Vertebrals five, usually longer than 
broad. Costals four, first longest, second and third highest, 
last smallest. Nuchal narrow. Marginals 11 on each side, 
ninth with superior border not much elevated anteriorly, 
supracaudals not united. Plastron large, extending forward 
about as far as carapace, its central region covered by the 
abdominal plates, united to carapace by a strong bridge. 
Anterior and posterior portions of plastron hinged, capable 
of closing shell completely when head and limbs are re- 
drawn. Gulars partly or completely united into a single 
plate. Pectoral median suture shortest. Abdominal suture 
longest. Anal suture next longest. Axillary and inguinal 
plates elongate, separating abdominal from marginals. Head 
rather large, somewhat pointed, covered with smooth skin. 
Chin and throat with a few barbules. Limbs covered with 
smooth skin except close to toes; anterior with five, posterior 
with four toes, completely webbed. Tail of moderate length, 
ending in a horny nail or claw. 
