THAI.ASSEMYDIDA;. 



157 



Of the second individual examined by Cope the first peripheral is at hand (fig. 193). It 

 has an obtuse free outer and an acute free inner margin. The thickness near the proximal 

 end and the outer border is 12 mm. At the hinder end (fig. 194) the thickness is somewhat 

 less. On the distal half of the bone and near the free margin, or rather, forming the free 

 margin, is a low sharp ridge, at which the upper and the lower surfaces meet. The suture with 

 the nuchal is oblique, running from the inner border forward and toward the midline, then 

 forward and outward, then again forward and toward the midline. The end of the bone was 

 somewhat overlapt by the nuchal. The length along the free outer border is about 65 mm.; 

 along the free inner border, about 40 mm.; from one extremity to the other, 80 mm. The 

 grea'test width is 35 mm.; that near the hinder end is 27 mm. 



The peripheral regarded by Cope as the sixth (fig. 195) has a length of about 100 mm. 

 A part of the free border is broken away. The bone is triangular in section, presenting thus 

 three faces. The inner or visceral face is quite concave the whole length and has in the 

 hinder half a deep conical pit for the end of a rib. The bone is about 30 mm. wide. The lower 

 face is slightly concave and is 30 mm. wide. The upper face has a width of from 35 mm. to 

 38 mm. and it is nearly plane. According to the present interpretation, the bone belongs to 

 the right side. All of the free borders are acute, especially the upper inner, and in none of 

 them is there any emargination. 



195. 



194 



FIGS. 193-195. Lytoloma jeanesi. Peripherals. X. No. 1473 A. M. N. H. 



193. Right first peripheral. 



194. Section near distal end of first peripheral. 



195. Section of siith? peripheral. Pit shown by interrupted line. 



Accompanying the bones above described is a fragment of a costal which agrees in its 

 dimensions with the one mentioned by Cope. Its width is 90 mm., while the thickness 

 thru the middle of the width is 1 1 mm. Cope states that the costals showed no sculpture. 

 However, the present costal has its surface broken by numerous pits of varying form and size, 

 resembling thus closely the costals of Osteopygis erosus. It is probable that the bone belongs 

 elsewhere. 



The peripheral described above as probably the sixth differs so much from the fifth of 

 L. angusta that a distinct species is clearly indicated. The ratios of width to length in the 

 two bones are very different. The width of the peripheral of L. angusta is contained in the 

 length about two and a third times; while in that of L. jeanesi the width is contained in the 

 length three and a third times. The results are equally decisive in case both peripherals 

 should happen to be fifths or sixths. It is wholly probable that neither of them can belong 

 farther backward in the series. 



The various measurements of this bone show that the carapace described by Wieland can 



not belong to L. jeanesi. 



Lytoloma wielandi sp. nov. 



Plate z8, figs. 7, 8; plate 29, fig. i; text-figs. 196, 197. 



Lytoloma angusta?, WIELAND, Amer. Jour. Sci. (4), xvm, 1904, p. 183, plates vi-viii, text-figs. 1-3; 

 Ibid., xx, 1905, p. 333, fig. 5. 



Dr. George R. Wieland has, with exprest doubts, referred some lower jaws, the front of a 

 skull, and a carapace of a Lytoloma to L. angusta. His specimens are in the Yale University 

 collection. The skull bones were secured by Professor O. C. Marsh from the upper Cretaceous 

 greensand bed at Hornerstown, New Jersey. The carapace came from Barnesboro. It seems 

 evident that these remains do not belong to the species to which they have been assigned, 

 and they are here made the types of a new species, named in honor of Dr. Wieland. 



