THAI.ASSEMYDID,*;. 



159 



dition showing that the turtles of this genus had not yet become seafarers. At Dr. Wieland's 

 disposal, belonging to this specimen, were wholes or parts of the third, fourth, fifth, and sixth 

 neurals, wholes or parts of two suprapygals, wholes or parts of all the costals of the right side 

 and of most of those of the left side, wholes or parts of all the peripherals of the left side behind 

 the third and of most of those of the right side behind the third, and a portion of the pygal. 

 The nuchal and the three anterior pairs of peripherals were missing. 



The neurals are hexagonal, with the broader end forward, and nearly as wide as long. 

 The third is 44 mm. long and 44 mm. wide; the fifth 41 mm. long and 41 mm. wide; the sixth 

 41 mm. long and 34 mm. wide. They are each 6 mm. or 7 mm. thick. The anterior suprapygal 



197. 



196. 



FIGS. 196 AND 197. Lytoloma wielandi. Carapace and sections of peripherals of type. 



196. Carapace. X}. After Wieland. c. p. i,c. p. 6, c. p. 8, first, sixth, and eighth costals; r. 1. 1, r. *. 4, first and 



fourth costal scutes; /, lateral fontanels; m. j. 5, m. s. 9, m. s. 12, fifth, ninth, and twelfth marginal scutes; 

 n-3, n.6, third and sixth neural bones; nu. />, nuchal bone; nu. s, nuchal scute; per. 2, per. 9, per. 

 n, second, ninth, and eleventh peripheral bones; py, pygal; spy. 2, spy. 3, second and third suprapygal 

 bones; v. s. I, v. s. 2, first and second vertebral scutes. 



197. Sections through middle of length of peripherals. Xj. The numeral on each indicates the position of the 



bone. The dotted line indicates the pit. py, section along middle of pygal. 



is 37 mm. long and 80 'mm. wide; the posterior, 60 mm. long and perhaps 80 mm. wide. The 

 posterior articulated narrowly with the pygal. 



The costals varied in width from 50 mm. to 60 mm. It is evident that the first costals 

 articulated with the nuchal at its outer extremities. Cope states that the nuchal ot 

 L. jeanesi articulated with the first neural, but he says nothing about the articulation with 

 the first costals. The latter species possest a nuchal extremely narrow, little wider than 

 the first peripheral, and therefore quite unlike that shown in Dr. Wieland's restoration. 



However, as Dr.Wieland's specimen lackt the nuchal and 

 the anterior peripherals, we do not know their structure 

 and connections. 



The eighth costal had its rib-end thrown back, so as 

 to enter a pit in the eleventh peripheral, a feature common 

 in the Cheloniidae. As in the Cheloniidx, too, there were 

 extensive fontanels between the distal ends of the costals 

 and the peripherals. 



