THALASSEMYDID. 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 
Fics. 196 AND 197.—Lytoloma wielandi. Carapace and sections of peripherals of type. 
196. Carapace. X4. After Wieland. c.p.1,c.p.6,c. p.8, first, sixth, and eighth costals; c.s.1,¢. 5.4, first and 
fourth costal scutes; f, lateral fontanels; m.s. 5, m.s.9, m.s. 12, fifth, ninth, and twelfth marginal scutes; 
n.3, .6, third and sixth neural bones; nu. p, nuchal bone; mw. s, nuchal scute; per.2, per. 9, per- 
11, second, ninth, and eleventh peripheral bones; py, pygal; spy.2, spy. 3, second and third suprapygal 
bones; v.5.1, v. 5.2, first and second vertebral scutes. 
197. Sections through middle of length of peripherals. 4. 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 of 
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 
Width. 
Peripheral. Length. —— and connections. 
Upper face.Inner face. The eighth costal had its rib-end thrown back, so as 
F _ 4 ie to entera pit in the eleventh peripheral, afeature common 
6 72 3 22 in the Cheloniidz. As in the Cheloniidz, too, there were 
8 80 56 15 extensive fontanels between the distal ends of the costals 
ae 75 se 3 and the peripherals. 
