THALASSEMYDID&. 
141 
Osteopygis borealis (Wieland). 
Plate 26, fig. 3; text-figs. 163-171. 
Osteopygis sopita, Cope, Proc. Acad. Nat. Sci. Phila. 1868, p.147; Vert. Cret. Form. West, 15 755 p- 258.— 
Hay, Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 441. 
Propleura sopita, Cope, Cook’s Geol. New Jersey, 1868 (1869), p. 735; Amer. Naturalist, t11, 1869, p. 88; 
Ext. Batrach., Rept., Aves N. A., 1869, pp. 140, 235, p. Vii, figs. 4-7, text-fig. 39. , 
Propleura borealis, W1ELAND, Amer. Jour. Sci., (4) xv, 1904, p. 1209, pl. ix; thid, XVIII, 1904, p. 190, 
fig. 4. 
Under Osteopygis sopitus the writer has presented his reasons for concluding that Cope 
erred when he referred to that species the specimen of Osteopygis which he described in his 
Extinct Batrachia, etc., p. 140, plate vii, figs. 4-7. 
The type of Wieland’s Propleura borealis is No. 778 of the Marsh collection, in the Yale 
University museum. It was obtained in 1870, from the upper bed of greensand, near Horners- 
isch 
Fic. 163.—Osteopygis borealis. The humerus, and parts of carapace, plastron and pelvis.» $. 
C. p. 1, ¢. p-2, etc., costal plates; um, humerus; /yo, hyoplastron; hypo, hypoplastron; #/, iltum; isch, ischiusn; 
n.1,m,2, first and second neurals; nu. p, nuchal plate; pub, pubis; x/ph, xiphiplastron. 1, 2, 3, etc., right 
and left peripherals. 
town, Monmouth County, New Jersey. It furnishes the nuchal and the first and the second 
neural; the second, third, fifth, sixth, and seventh right peripherals; the first, second, 
third, fifth, and sixth left peripherals; the first, second, fourth, and fifth right costals; the first 
and second left costals; the right hyoplastron and hypoplastron; both xiphiplastra; the 
left humerus; the left pubis and ilium; and both ilia. These bones are in a fine state of 
preservation. 
