dermatemydida:. 



241 



o 



\\ idely the gulars. It was probably divided. The gulars are of rather peculiar form, extending 

 utward and backward toward the outer hinder angle of each epiplastron. The humero- 

 pectoral sulcus is so obscure that its course is uncertain, but it appears to run where indi- 

 cated in the figure. If this is correct, it did not cross any part of the entoplastron. The 

 pectoro-abdominal sulcus and the abdomino-femoral are distinct and as shown in the figure. 

 The course of the femoro-anal is as represented in the figure. Of the inframarginal series, 

 only a small portion of one axillary scute is seen. The sculpture of the lower surface is hardly 

 to be determined, the result of weathering. 



Both first peripherals are present (plate 34, fig. 7; text-fig. 301). The antero-posterior 

 length is 65 mm.; the length along the free border, 64 mm.; along the hinder border, about 

 halt as much. The thickness, as stated, is 20 mm. The upper surface of this bone is gently 

 convex; the lower surface is strongly convex antero-posteriorly. Close to the anterior border 

 above there runs a shallow groove, so that the free border appears somewhat everted. On the 

 lower surface the sutural face for articulation with the nuchal is excavated for the short costi- 

 form process of the latter. The same excavation appears in the first peripheral of Leidy's 

 type of the species (fig. 300). 



The marginal scutes did not extend upward quite half-way on the peripheral. Only a 

 fragment of the second peripheral is present. The form of the nuchal bone can only be inferred 

 from the sutural edges of the adjoining first peripherals. It seems probable that its right and 

 left sides made a sharper angle with each other than they do in A. punctatus. It is extremely 

 probable that the front border of the nuchal measured between 65 and 70 mm. The front of 

 the first vertebral scute would then measure about 130 mm. 



There are present fragments of various costals and bridge peripherals. The proximal end 

 of a costal, probably the left third, has a width of 50 mm. and a thickness of 1 1 mm. The 

 sulcus bounding laterally the two vertebral scutes of which it bears parts is distant 25 mm. 

 from the suture made with the neural. These vertebrals were then about 80 mm. wide, much 

 narrower than the first vertebral. The distal end of another costal is 60 mm. wide and 8 mm. 

 thick. It is crost by a sulcus which runs from 17 mm. to 45 mm. above the lower or distal end. 

 A bridge peripheral is represented by the end which joined the costal. It is 57 mm. wide and 

 6 mm. thick. On its inner surface is a broad, shallow groove for the extremity of the rib, and 

 a portion of the rib extended beyond the border of the costal plate at least 50 mm. Another 

 fragment, which appears to be part of a peripheral near one of the buttresses, indicates that a 

 rib sent its free extremity down deep into the bone forming a gomphosis, as in Zygoramma. 



The costals and the peripherals are ornamented with shallow pits separated by low, 

 rounded walls, and are arranged somewhat in rows. On the outer ends of the costals and 

 peripherals the sculpture is often obscure. 



Adocus lacer sp. nov. 

 Plate 34, fig. 8; plate 36, fig. 1; text-figs. 3(^-307. 



The type of this species belongs to the Cope collection in the American Museum of Natural 

 History. Its number is 1350. There is no history regarding the origin or the finder of the 

 specimen, but there is no doubt that it was obtained from the upper greensand bed of the 

 Cretaceous of New Jersey. There is nothing to indicate to what species Cope referred it. 

 The materials include the greater portion of the plastron, the nuchal, the three anterior periph- 

 erals of both sides and a small portion of the left front costal. 



The species is characterized by a plastron (plate 36, fig. 1 ) which is elongated in proportion 

 to the width of the base of the hinder lobe. The bridge likewise is longer, in relation to the 

 width of the hinder lobe of the plastron, than in any of the other species. In width of bridge, 

 in relation to the length of the plastron from the entoplastron to the rear of the xiphiplastrals, 

 A. agllis exceeds it. The hinder lobe resembles most that of the species just named, but the 

 lateral borders are not so uniformly curved and there is on the upper surface a groove parallel 

 with the free edge. The dimensions of the various parts are to be obtained from the table 

 on page 242. 



The anterior lobe is not represented in front of the hyoplastron, except by about one- 

 fourth of the entoplastron. The latter has had a width of about 88 mm. The free border of 

 16 



