126 University of California Publications in Geology [Vol.12 



dichotomously a short distance from the peristome, branch again two- 

 thirds the distance from the mouth to the margin, and continue on the 

 upper surface as faint lines. 



Related forms. — In general appearance this species resembles Den- 

 draster gibbsii (Remond) , but has been separated from it on account of 

 its less eccentric apical system, longer petals of the bivium, smaller 

 angle between the petals of the bivium, and in that the petals are 

 usualh' broader. From the variety D. hesperis var. gibbosus Kew it 

 differs in lacking the great transverse breadth of test and the ex- 

 treme elevation of the summit, or abactinal hump. It may easily be 

 separated from D. arnoldi Twitchell and B. coalingaensis Twitchell 

 on account of its smaller sized tubercles, which are of the same size 

 over the test, whereas in the latter two forms the tubercles are larger 

 on the interporiferous areas of the petals. 



Geologic Jiorizon. — Pecten coalingaensis zone of the Upper Etche- 

 goin formation. Upper Pliocene. Occurs associated with Bendr aster 

 gibbsii (Remond) and D. hesperis var. gibbosus Kew. 



Localities. — Coalinga district, Fresno County, California ; holotype 

 from Univ. Calif, loc. 3004. 



DENDEASTEE HESPEEIS GIBBOSUS Kew, n. var. 

 Plate 26, figures 2a, 2b 



Holotype.— ^o. 11022 Univ. Calif. Coll. Invert. Pal. 



This form differs from Dendraster hesperis Kew in having the 

 transverse diameter considerably greater than the anteroposterior di- 

 ameter ; and in that it possesses a prominently elevated abactinal sur- 

 face, which gives the test a humped appearance ; also the rows of pores 

 tend to converge more in the distal ends of the petals. 



Geologic horizon. — Upper Etchegoin formation. Upper Pliocene; 

 associated with Dendraster hesperis Kew. 



Localities. — Holotype from Coalinga district, Fresno County, Cali- 

 fornia, Univ. Calif, loc. 525 ; all other specimens from the same region. 



DENDEASTEE JACALITOSENSIS Kew, n. sp. 

 Plate 25, figures la, lb 



Holotype.— ^0. 11034 Univ. Calif. Coll. Invert. Pal. 



Size large. ]\Ieasurements of holotype : anteroposterior diameter 

 61.4 mm., transverse diameter 63.7 mm., greatest height 10.5 mm. 

 Test depressed, and noticeably thin at the margin ; outline subpen- 



