244 FOSSIL TURTLES OF NORTH AMERICA. 



can be no doubt that they were found in the Cretaceous greensand of New Jersey. There 

 are present the left first, ninth, tenth, and eleventh peripherals, a part of the suprapygal, 

 some fragments of costal bones, the left half of the entoplastron, the left hypoplastron, and 

 the right xiphiplastron. Fig. 302 represents the piece of the entoplastron. When complete 

 it was 56 mm. long, 80 mm. wide, and 18 mm. thick at the hinder border. The intergular 

 scutes encroacht on the front of it and the pectorals on the hinder border. The hinder lobe 

 was 173 mm. wide at the base and about 135 mm. long. The left hypoplastron is 103 mm- 

 long. At the midline, between the inguinal notches, it is 28 mm. thick. Fig. 303 represents 

 the outline of the right xiphiplastron, seen from below. It agrees in form with that of 

 the type of the species, and shows that the hinder end of the plastron was broadly rounded. 

 At the middle of the suture with the corresponding hypoplastron it is 18 mm. thick. There 

 was, near the outer border, a stout process that fitted into the hypoplastron. On the upper 

 surface is a large depression for the pubic bone. In the midline, at the hinder ends 

 of the xiphiplastra there is a considerable elevation, and here the thickness of the bone is 

 20 mm. 



Both the hypoplastron and the xiphiplastron are pitted, the latter most distinctly. The 

 surface of the entoplastron is irregularly pitted. 



Fig. 304 presents a view of the first left peripheral, and this may be compared with that 

 of A. beatus and that of A. punctatus. It measures 61 mm. along the free border and 68 mm. 

 at right angles to this. Its greatest thickness, where it joins the nuchal, is 20 mm. It will be 

 observed that the arrangement of the sulci differs from that of the type and resembles more 

 that of A. punctatus. It is to be concluded that the scutes here were somewhat variable in 

 their development. The free border of the bone is somewhat reverted, as in the type. 



The three hinder peripherals are narrow and high (fig. 305). The ninth has a width of 

 65 mm. and a height of 100 mm.; the tenth a width of 60 mm. and a height of 95 mm.; the 

 eleventh a width of 58 mm. and a height of 68 mm. With the latter peripheral is a portion 

 of the suprapygal. Evidently, as in A. punctatus, the costo-marginal sulci ran at some 

 distance above the peripherals. A part of the fifth vertebral scute appears high up on the 

 suprapygal. Figs. 306 and 307 represent the hinder sutural faces of the ninth and eleventh 

 peripherals. 



On the upper borders of the ninth and tenth peripherals are seen remains of the extrem- 

 ities of the ribs of the seventh and eighth costals, which extend down into the peripherals. 

 On fragments of the bridge peripherals are seen the rib-ends lying in shallow grooves on the 

 inner surfaces, sometimes extending downward as much as 50 mm. Other fragments of 

 bridge peripherals show that the transition from the upper to the lower surfaces was rather 

 abrupt, there being a decided but rounded angle where the turn was made. 



The peripherals and the costals are all ornamented with pits, arranged mostly in oblique 

 rows. There are about 5 pits in a line 6 mm. long. 



Adocus syntheticus Cope. 

 Plate 36, fig. 2. 



Adocus syntheticus, COPE, Proc. Amer. Philos. Soc., XI, 1870, p. 515 (name only); Ibid., p. 548; Op. 

 cit., xii, 1871, p. 44; Vert. Cret. Form. West, 1875, p. 262. HAY, Bibliog. and Cat. Foss. Vert. 



N. A., 1902, p. 444. 



Professor Cope's first reference to this species did not bear with it any description. The 

 species was said to be based on a plastron lacking the entoplastron, the right epiplastron and 

 the right hypoplastron, a peripheral bone from the bridge, 2 imperfect costals, and some 

 smaller fragments. This type is now in the American Museum of Natural History, and has 

 the number 1466. All the parts originally described are present, except the hinder extremity 

 of the right xiphiplastron. The "marginal from the bridge" is a part of the right hypoplastron. 

 The specimen was found in the upper bed of the Cretaceous greensand, at Barnesboro, New 

 Jersey. 



Professor Cope states that the length of the plastron is 484 mm. This is probably a mis- 

 print for 454 mm., which appears to be nearer to the correct length. The plastron as a whole 



