40 CINOSTERNID &. 
a. 9, spir. Washington. Smithsonian Instit. 
b-c. Yg., spir. Florida. HK. Doubleday, Esq. [ P.]. 
d. Yg., skel. Florida. EK. Doubleday, Esq. [| P. |. 
e-h. 3,2, & her., spir. New Orleans. Ki. Doubleday, Esq. | P.]. 
t-k. Yg., spir. New Orleans. (Types of C. hippocrepis.) 
l,m,n. 3 Q, stfid. Louisiana. 
0, p. &, stfid. N. America. (Types of C. oblongum.) 
g. Her., shell. N. America. (Type of C. doubledayti.) 
r. Yg., spir., very bad state. N. America. (Type of C. punctatum.) 
s. Q, stfid. N. America. HK. Doubleday, Esq. [P.]. 
tu. Ye., spir. N. America. Sir E. Belcher [ P. ]. 
v,w. 2 & her., shells. N. America. - 
x. 9, spir. f (Type of Swanka fasciata.) 
y. 9, skel. ——? 
z P. Her., stffd. —? 
The latter specimen, referred with some doubt to this species, is 
specimen c of Gray’s C. hippocrepis. As already noticed by Gray, 
it is anomalous in having the pectoral and abdominal shields united ; 
it differs also from all Cinosterna in having only 21 shields round 
the margin of the disk, instead of 23. The carapace is much more 
depressed than in C. hippocrepis, of which it is, however, perhaps 
only an anomalous specimen. 
Cinosternum sonoriense, Leconte, Proc. Ac. Philad. 1854, p. 184 
(Thyrosternum sonoriense, Agassiz, Contr.1. p. 428, pl. v. figs. 8-11), 
appears to be very closely allied to the preceding species. The dif- 
ferential characters have not been clearly defined.—Hab, Arizona. 
5. Cinosternum flavescens *. 
Platythyra flavescens, Agassiz, Contr. N. H. U. S.i. p. 430, pl. v. 
figs. 12-15 (1857). 
Cinosternum flavescens, Cope, Check-List N. Am. Rept. p. 52 
(1875); Coues, in Wheeler’s Explor, Surv. W. 100th Mer. v. 
pl. xvii. (1875). 
Jaws weak, beak not hooked. Nose short. Suture between the 
pectorals nearly as long as that between the humerals (in the adult). 
Otherwise apparently like C. pensylvanicum, but stouter. Yellowish 
green, shields edged with black ; beak unspotted. 
Length of shell 11 centim. 
Arkansas, Western Texas, and Gila River. 
6. Cinosternum henrici. 
Cinosternum henrici, Leconte, Proc. Ac. Philad. 1859, p. 4; Yarrow, 
in Wheeler's Rep. Explor, Surv. W. 100th Mer. v. p. 583, pl. xvi. 
(1875). 
Swanka henrici, Gray, Suppl. Cat. Sh. Rept. i. p. 69 (1870). 
* This species has never been described, and rests on the generic description 
published by Agassiz, in which nothing but cranial characters are given, and 
on the two figures quoted, Agassiz’s being that of a quite young specimen. 
