1877.) 229 
(Cope. 
CIsTUDO MARNOCHII. 
Represented by the posterior lobe of the plastron of an individual of 
twice the bulk of the existing North American Cistudos. It is broadly 
rounded posteriorly, and there is an emargination at the femoro-anal der- 
mal suture. The anterior suture is straight, as is also the lateral, which 
Measures more than a third the length of the entire lobe. On the upper 
side of the angle included by these suturess the fossa for fixed attachment 
with the carapace. The beveled face of the fore edge of the lobe is quite 
wide. The dermal sutures are well marked. The anal scuta are large, 
their median length being half that of the lobe. The common femoral 
suture is only half as long as the ventral. The inferior surface is nearly 
flat in every direction; and the surface is smooth. The posterior border of 
the specimen is broken away. 
This species was obtained from the same formation as the last, by Gabriel 
W. Marnock, to whom I dedicate it. 
ANCHYBOPSIS BREVIARCUS sp. nov. 
The genus to which the above name was given, was established by the 
writer in 1870, for a species Cyprinoid fish, from the pliocene formation of 
Idaho. Its affinities were then stated to be to Alburnops (Hybopsis), and 
related existing genera. The present paper describes two additional spe-: 
cies of the genus, both of whichare represented by pharyngeal bones and 
teeth of both sides. The teeth are shown to be 5-5, in contradistinction to 
the genera Hemitremia and Alburnops, where they are 5-4 and 4-4 respec- 
tively E 
In this fish the common base of the pharyngeal teeth rises upwards, so 
as to project well in front of the general plane of the bone. The superior 
teeth are more compressed than the inferior, and the first and second count- 
ing from below, have convex grinding faces. The pharyngeal bone has a short 
inferior and a long superior limb. The alate portion is regularly and 
strongly convex, without abrupt expansion. The nutritive foramina of the 
anterior face are two large inferior and several small superior ones. 
Measurements. M. 
Vertical extent of bone in a straight line............... 020 
Width at second tooth. ...... 0... cece cece eee eens .008 
«at first SO os aa aeemess setesaeiaadndennes -004 
Length of tooth line... .... cee cece ee cece ee enter ene O11 
es Of third: COOH: 0:0. ese jrecaainai ee oecies sana ten sas .005 
me of basal limb to first tooth................00.00- -009 
This species is of smaller dimensions than the A. latus. 
ANCHYBOPSIS ALTARCUS sp, nov. 
The pharyngeal bones of this cyprinoid are larger and of more slender 
proportions than those of the A. brevtarcus. Specimens from both sides are 
preserved. The inferior and superior limbs are both elongate, the former 
slender, the latter flat. The alaisabruptly expanded at right angles to the 
long axis; the external border is thence nearly straight to, and the angle of 
