434 University of California Publications in Geology t VoL - 11 



The line separating the smooth base from the ornamented distal portion 

 runs obliquely upward from anterior to posterior at an angle of about 

 45°. The lateral faces are slightly rounded. The inserted portion 

 tapers to a quite sharp point in which the groove is wide open, shallow 

 and has sharp edges. There is but slight indication of the arrange- 

 ment of the tubercles in rows. 



1 2 



Fig. 1. Cosmacanthus humboldtensis, n. sp. Lateral surface of spine. Type 

 specimen no. 9162. X 1%. 



Fig. 2. Cosmacanthus humboldtensis, n. sp. Posterior surface of spine. Type 

 specimen no. 9162. X 1%. 



This spine resembles many other Ichthyodorulites in having bilat- 

 eral symmetry, a smooth inserted portion and the exserted portion 

 partly ornamented by sculptured tubercles. 



From the description of Cosmacanthus Agassiz by Woodward 4 it 

 probably belongs to that genus. 



It differs in many respects from Cosmacanthus elegans Evans from 

 the Lower Triassic of Idaho. Although the upper end is broken off, 



4 Woodward, A. S., Catalogue of the fossil fishes in the British Museum, pt. 2, 

 p. Ill, 1891. 



