266 FOSSIL TURTLES OK NORTH AMERICA. 



mm. in front, 30 mm. behind, there was a more prominent lateral keel. Along none of these 

 keels was the bone suddenly sunken just behind the transverse sulci, as it is in H. crassa. 

 In addition to these keels, there is on each side, on the bridge peripherals, a narrow ridge 

 which passes in front and behind into the free edges of the peripherals. 



The rim of the carapace was formed by a nuchal, probably ten pairs of peripherals, and 

 a pygal. The nuchal is excavated in front for the neck. The width in front is 43 mm,; its 

 thickness is 11 mm.; its length can not be determined. The first peripheral is 32 mm. long 

 on the free border and 38 mm. high. The second peripheral is 35 mm. long, concave above, 

 convex below, and with an acute border. Farther backward this border runs into the rather 

 sharp keel running along near the upper border of the bridge peripherals. The upper border 

 of the bridge peripherals is plane, continuous with the surface of the costals, and 10 mm. 

 or less wide. At the bottom of this surface just above the keel before mentioned run the 

 sulci separating the costal scutes from the marginals. Immediately below the lateral 

 keel the peripherals thicken suddenly and form a sort of roll along the shell. The form of 

 this roll may be seen from the section of the peripheral of the next species, H . paludosa. 

 The peripherals behind the bridge are slightly flared upward and are acute-edged. The 

 width and length of the pygal can not be determined. The hinder border of the carapace 

 was not notcht. 



The anterior costal plate had a width of about 50 mm.; the next 3 or 4 pairs, a width of 

 35 mm. or a little more. The costals opposite the bridges have a thickness of 7 mm. at their 

 distal ends. 



The neurals are broad, and with the broader end forward. The second has a width of 

 about 35 mm.; the third about the same width; the fourth a width of 25 mm. The boundaries 

 of those behind these can not be determined. The second vertebral scute has a width of 

 about 75 mm.; the succeeding ones are narrower. 



The anterior lobe of the plastron (fig. 327) is about 100 mm. wide at the base. It appears 

 probable that the epiplastrals are missing. The entoplastron appears to have the form 

 and size represented in the figures. The epiplastra were probably in contact with the outer 

 border of the hyoplastra as in Staurotypus salvinii ( Boulenger's Catalogue, p. 31 ). The bridge 

 has a width of about 60 mm., a little more than half of which is furnisht by the hyoplastron. 



The hinder lobe of the plastron is about 70 mm. wide at the base. The suture between 

 the hypoplastic and the xiphiplastra was probably where shown in the figures, but this is not 

 certain. The xiphiplastra probably came to a point posteriorly. 



Of Staurotypus salvinii, Sumichrast says (Bull. Soc. Zool. France, 1880, p. 169) that it 

 lives in muddy pools. Its food consists of small aquatic animals, especially ot mollusks 

 belonging to the genus Ampullaria. Its disposition is voracious and irritable. Its gait on 

 hind is free, and it runs with some swiftness, a tact due to the form of the plastron, which 

 leaves to the limbs freedom of motion. 



The small posterior lobe of the plastron of Hoplochelys indicates that the hinder limbs 

 were strong and endowed with freedom of movement. Irs habits and disposition may have 

 been not greatly different from those of Staurotypus. 



Hoplochelys paludosa sp. nov. 

 Fig. 32S. 



This species is based on a single peripheral bone, probably the seventh of the left side. 

 It was found by Mr. Barnum Brown, in 1904, in Escavada Canyon, New Mexico, where H . 

 talit m was discovered. It belongs to the American Museum of Natural History and has the 

 number 6079. It differs from the latter species in lacking the longitudinal ridge along the 

 convexity of the outer surface of the peripherals, and in having the suture with the costals 

 much higher above the costo-marginal sulci. In the present species this suture is at a distance 

 of 20 mm. above the sulcus, while in H. saiit-us it is only 10 mm. or less. The absence of the 

 peripheral carina is regarded as an important specific character. The size of the individual 

 has been probably slightly less than that of H. saliens, the length of the seventh peripheral 

 of the lam j r being 35 mm.; of //. paludosa, 32 mm. 



