HOLOSAURUS ABRUPTUS MARSH 351 
bladelike bone, the interclavicle. In 1880 Marsh’ stated: “In 
Holosaurus there appears to have been a partially ossified mesoster- 
and in 1889 Dollo? mentioned the presence of an interclavicle 
num;”’ 
Fic. r.—Pectoral girdle of Holosaurus abruptus. One-seventh natural size. Ic, 
interclavicle; c, coracoid; s, scapula; A, humerus. 
in Plioplatecarpus. Williston’ discovered the existence of this ele- 
ment in Platecarpus in 1899, but up to the present time it has never 
been figured. The interclavicle in this specimen is slender, rounded 
Fic. 2.—Pelvic girdle of Holosaurus abruptus. One-sixth natural size. P, 
pubis; 7s, ischium; J, ilium. 
laterally at both ends, and differs from that described for Platecar pus 
in that it has no apparent articular facets at the anterior end. 
The calcified sternum of the specimen is preserved in the chalk, 
but no description of this will be attempted in the present article, as 
t American Journal of Science, Vol. XIX (1880), p. 841. 
2 Bull. Soc. Belg. Geol. Pal. Hyd., III (1889), 286. 
3 Kansas University Quarterly, Vol. VIII, No. I (January, 1899), p. 39. 
