260 



University of California. 



[Vol. 3. 



forking heads articulating on small and widely separated diapo- 

 physes and parapophyses. Caudal vertebrae with single-headed 

 ribs and Y-shaped lower arches. Limbs tridaetyle, with a rudi- 

 mentary fourth digit. Propodial and epipodial segments elon- 

 gated. Elements of epipodial segments separated by a wide cleft. 

 Posterior limbs equaling or excelling the anterior in size. Ilium 

 long and slender. Pubis very broad, with obturator foramen. 



Toretocnemus californicus, n. sp. 

 Pl. 24. 



This species is represented by a specimen (No. M 8100 

 University of California Palaeontological Museum) embedded in 

 a slab which had been weathered in such a manner that a large 

 portion of the skeleton was carried away. There remain nearly 

 all of the ribs, the middle and posterior dorsal and the anterior 

 caudal vertebra^, the pelvic arch, both hind limbs, and the right 

 anterior limb. The type specimen was discovered by Miss A. M. 

 Alexander in the Upper Triassic limestones at Bear Cove, three 

 miles north of Brock's Ranch, on Pitt River, Shasta County. 



Vertebra- and ribs. — About thirty vertebra' are present, two- 

 thirds of the number being behind the pelvic arch. The centra 

 are all deeply biconcave and have a length equal to about half 

 their height. On the most posterior vertebra? the upper arches 

 are about a third higher than the centra and have rather thin, 

 sharply recurved spines. The zygapophyses are here i*e pre- 

 sented by notches. The diapophyses on these vertebrae are a 

 trifle below the middle of the centrum. Immediately behind the 

 pelvis the upper arches become higher, broader, and more nearly 

 erect and the zygapophyses are better developed. In this region 

 the diapophyses are low down on the sides of the centra and are 

 considerably elongated vertically by swinging downward and 

 forward to the anterior margin. Below the contact of two of 

 the caudal centra there is a V-shaped lower arch like those 

 known in Shastasaurus perrini. 



Near the middle of the dorsal region the diapophyses are small 

 and round and lie above the middle of the side of the centrum, 

 while prominent parapophyses with backwardly directed facets 

 are present low down and nearer the anterior margin (PI. 24, 

 fig. 4). 



