248 FOSSIL TURTLES OF NORTH AMERICA. 
Mr. Barnum Brown, on Hell Creek, Montana. Fragments of costals scarcely, if at all, to 
be distinguisht from them are found in the collection made 1 in the Judith River region for 
Peoieccor Cope, by C. H. Sternberg, in 187 6. It is the writer’s opinion that it is ameate to 
identify as belonging to Adocus lineolatus specimens from the Judith River and the Laramie 
beds before far beter materials of the species have been collected from the type locality. And 
when these better materials have been secured from Bijou Creek, better specimens than yet 
obtained must be secured from the other formations mentioned. It is improbable that the 
same species continued from the Judith River epoch to the Arapahoe epoch. Meanwhile, 
even good fragments are worth preserving. 
The specimen referred to above as having been collected by Sternberg from the Judith 
River region forms No. 6105 of the American mivlaceun It belonged to ne third or the fifth 
costal. Its width is 32 mm.; its thickness, only 3.5 mm. There is no thickening along the 
middle on the under side corresponding to the rib. The outer surface 1s crost by the costo- 
vertebral sulcus. The ornamentation resembles in pattern that of Cope’s Compsemys 1m- 
bricarta (Basilemys imbricaria), and Cope has so labeled the bone; but the size of the areole is 
considerably smaller, there being 4 pits in a line 5 mm. long, instead of 3 or less. The ridges 
between the areola are low and run at right angles with the sutural borders of the bone. 
A fragment of a costal from Hell Cheek, Momeanar collected by Mr. Barnum Brown, is 
catalogged under the number ror4 of the American Museum. ‘The costal is 36 mm. wide 
and 5 mm. thick. The sculpture is similar to that of the Judith River specimen just 
described, but is more obscure. 
A peripheral, the second of the left side, has the number 1o14, but it belonged to a much 
larger individual. It is represented by figs. 308 and 309. ‘The bone is 55 mm. high, 48 mm. 
———"4 along the free border, and 32 mm. along the 
aN costal border. Fig. 309 represents the border 
\ \ joining the first peripheral, the greatest thick- 
ae ness being 16 mm. ‘The sutural border for the 
fineness ascribed to the costal. It resembles 
apes greatly that of the fragments numbered 6103 
Fics. 308 AND 309.—Adocus lineolatus. Periph- A. M. N. H. and deseribed under Basilemys 
eral and section. X4. No. 1org A. M.N.H. imbricarta. 
No. 6107 A. M. N. H. includes a fragment 
of a costal plate and another of a plastral bone 
which were collected for Professor Cope, in 1877, 
by Mr. J. C. Isaac, in the Laramie of Converse County, Wyoming. The sculpture of these 
bones resembles closely that of 4. lineolatus, type. 
\ : | = S\ 309. 24mm. The sculpture has the pattern and the 
308. Second left peripheral. 
309. Section of sare peripheral at union with third. 
Genus AGOMPHUS Cope. 
Shell thick and heavy in the known species. Free borders of the carapace thickened and 
obtuse. Exposed surfaces of the shell not pitted. Hinder marginal scutes not rising on the 
costal bones, except slightly in one species. Inframarginal scutes present. The pectoral 
scutes extending forward to the hinder end of the epiplastrals. Intergulars not known. Nuchal 
with costiform processes. Rib-heads more strongly developt than in Adocus. 
Type: A gomphus turgidus Cope. 
The genus 4 gomphus was founded by Cope in 1871 (Proc. Amer. Philos. Soc., x11, p. 46) 
having 4. turgidus as the type. The only character given was the apparent lack of gomphosis 
between the costals and the pea ee an insufhcient character, if a true one. In 1882 
(Pr roc. eas Betas Soc., Xp 145) pa ce sa se Dermate omys In the Emy- 
nen a robes: of che ae ade The same eae are Phe in that author’s Vertebrata 
of the Tertiary Formations of the West, in 1884. In both the publications referred to, the 
genus Amphiemys was placed among the Adocidz. Baur in 1888 ( Zool. Anzeiger, X1, p. 595) 
redae ed Amphiemys to the position of a synonym of 4 gomphus and arranged the latter under 
third peripheral has a maximum thickness of 
