BAENID. IOI 
the hinder lobe is not given, but its posterior extremity was 35 mm. wide, truncated, and 
with rounded angles. It was shorter than the anterior lobe. Its thickness in the inguinal 
region was 10 mm. 
The surface of the plastron was obsoletely, but coarsely, rugose; roughest in front, where 
the sculpture consisted of short, raised lines irregularly disposed. 
The intergulars were distinct. These were followed by a pair of interhumerals, which were 
longer than ide and crowded the humerals away from each other, and they seem to have 
extended themselves backward between the pectorals likewise. The pectoro-humeral sulcus 
appears to have been advanced well forward. Cope states that it was impossible to determine 
whether or not “intermarginal” scutes were present, and that if they existed their position was 
quite external. It is probable that by “intermarginals”” was meant inframarginals. 
The carapace is stated to have possest an openly dentate posterior horden The surface 
was irregularly swollen, especially along the margins of the vertebral scutes. The latter were 
wide; the marginals are said to be narrow, by which is probably meant that they rose but a 
short distance from the free margins. 
The description of this species given by Cope indicates that it was related to Baéna rather 
than to Adocus. The thoro co-ossification of the bones, so that the presence of mesoplastrals 
could not be proved or disproved, the uneven surfaces of the shell, the notcht border of the 
carapace, all point toward Baéna. At the same time, the presence of the interhumerals 
marks it off as different from all North American turtles hitherto described. Archeochel ys 
(Lydekker, Cat. Foss. Rept., pt. 11, 1889, p. 219), from the Wealden of England, has the 
humerals separated by what has been regarded as an intergular, but which is quite as likely 
an interhumeral. Behind this come in succession an interpectoral, an interabdominal, 
and an interfemoral. The latter extends itself backward between the anals also. That is, the 
scutes which usually join in pairs along the median line are here separated the length of the 
plastron by a series supposed to be azygous. These median scutes in both Polythorax and 
Archeoc helys are probably homologous win the median series of Dermochelys. ; 
Mr. Lydekker places his genus 5 provisionally i in the Amphichelydia. 
Genus NAOMICHELYS nov. 
A genus known only from the entoplastron. Outer surface ornamented with elevations 
resembling small shot. A long narrow scute (intergular or interhumeral) occupies most of the 
length of the bone. Gulars ? and humerals? present. 
Type: Naomichelys speciosa Hay. 
The relationships of this genus are not certain. It may belong among the Pleurosternidz 
rather than among the Baénide. It is here put in the vicinity of Polythorax. 
Naomichelys speciosa sp. nov. 
Plate 40, figs. 2, 3. 
The only portion of this species at present known is an entoplastron which was collected 
in 1904, by Mr. Barnum Brown, of the American Museum of Natural History. It was secured 
in the Upper Jurassic, Morrison beds, 25 miles east of Pryor, Montana. The catalog number 
is 6136. The bone is complete, except that the extreme anterior end is broken away. The bone 
is 85 mm. long, and was originally about 10 mm. longer. The width is 78 mm. The thickness 
is quite uniformly close to 7 mm. Where the bone joined the epinlastia the upper surtace 
extends out a little farther than the lower. The hyoplastrals overlapt extensively the ento- 
plastron, as may be seen from plate 42, fig. 3. Fig. 2 of the same plate shows the scutes and 
the ornamentation of the inferior surface. Five scutes are represented in the bone. There 
is a long median scute which narrows forward, as well as backward. It seems probable that 
anteriorly i it did not extend beyond the bone. This scute may be the intergular which was 
crowded backward by the eulars as in GC lokagi noveguinee (Boulenger, Cat. Chelonians, 
pl. vi), or it is possibly an interhumeral « ran interpectoral. Attention is called to Cope’s 
Polythorax and Lydekker’s Archeochelys. 
On each side of the scute just described is another which may be either an intergular or a 
gular. Behind this is a large scute which is assumed to be the humeral. 
