228 COPE. [Vol. VII. 



wards (.? epigastroid cartilage). The ischium is transverse in 

 position, and somewhat expanded distally, sending forward a 

 membranous sheet to the pubis. Posteriorly it gives origin to 

 a cartilaginous rod (hypogastroid) which speedily joins its fellow, 

 and continues with it as a double median cartilage, terminating 

 acutely. This cartilage resembles that already described in 

 Pygopus, where, however, the two do not meet on the middle 

 line. Posterior limb. This is a little longer than the ilium. It 

 consists of femur, tibia and fibula about two-thirds as long ; and 

 tarsal and metatarsal elements, all closely adherent. The former 

 are three in number, and the latter two. 



Observations. In the figure by Dumeril and Bibron of the 

 scapular arch, the procoracoid is omitted. The pelvis has been 

 drawn from a dried specimen where the inferior arches have 

 been divided and the lateral elements widely separated. The 

 cartilages are not represented. 



Ophisaurus ventralis L. pi. XIII, Fig. 4. Described by 

 Miiller, I.e., Dumeril and Bibron,^ Cope^ (scapular arch in part), 

 Furbringer ^ and Shufeldt.* Southern parts of North America 

 east of the Rocky Mountains. 



Scapular and pelvic arches present ; no anterior limbs ; pos- 

 terior represented by a minute rudiment, which is not visible 

 externally. 



Scapular arch. All the elements present, but more or less 

 rudimental. Clavicles well developed, simple, and nearly meet- 

 ing distally. Scapula cartilaginous, coracoid osseous, with a large 

 cartilage which is produced anteriorly and is continuous with 

 the small cartilaginous procoracoid. Interclavicle posterior to 

 the coracoid cartilages and overlapping the anterior border of the 

 sternum ; its anterior limb very short, the posterior still shorter; 

 sternum transverse, subcrescentic, cartilaginous, not supporting 

 any ribs. 



Pelvic arch. Ilium short, proximally in contact with a single 

 vertebra, distally confluent with the rudimental pubis and 

 ischium, which form together an oval plate, entirely lateral in 

 position. 



1 Erp. Gen., Atlas, VII, Figs. 5-9. 



2 Proceed. Acad., Phila., 1864, p. 228. 



8 I.C., pp. 14, 43, PI. I, Fig. 8 ; PI. Ill, Fig. 36. 

 * Proceed. U. S. National Museum, 1882, p. 397. 



