PLEISTOCENE ECHINODEEMATA. 223 



Family STRONGYLOCENTROTID.F. 



Genus STRONGYLOCENTROTUS Brandt. 



STRONGYLOCENTROTUS DROBACHIENSIS Mullei'. 



(?) Echinus granulatus, Billings, 1S56, Canadian Naturalist and Geologist, 1st ser., vol. 1, p. 346. 

 Strongylocentrotus drbbaehiensis Yen-ill, 1S75, Am. Jour. Sci., 3d ser., vol. 10, p. 375. 

 Strongylocentrotus drbbachieiisis Cooper, 1894, California Min. Bur. Bull. 4, p. 32. 



Description. — Fragments of tests and spines regarded as representing this species have been 

 reported from Pleistocene deposits from Nantucket northward and also in California. 



Localities. — Canada (Billings) ; Sankat}^ Head, Nantucket, Mass. (Verrill) ; San Nicolas 

 Island, Cal. (Burns). 



Geologic horizon. — Pleistocene. 



Collection. — Unknown. 



Strongylocentrotus franciscanus A. Agassiz. 



Strongylocentrotus franciscanus Arnold, 1903, California Acad. Sci. Mem., vol. 3, p. 90. 

 Strongylocentrotus franciscanus Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 706. 



Description. — Arnold in discussing the occurrence of this species in the Pacific coast Pleis- 

 tocene says: 



This is the large sea urchin of the west coast. Spines which are probably of this species have been found in the 

 lower San Pedro series of Deadman Island. The spines of this species are distinguishable by their large size and longi- 

 tudinal striations. Some of the spines found are 20 millimeters long and 3 millimeters in diameter. 



Locality. — San Pedro, Cal. 



Geologic horizon. — San Pedro formation (lower part), Pleistocene. 



Collection. — Leland Stanford Junior University. 



Strongylocentrotus purpuratus (Stimpson) . 



Strongylocentrotus purpuratus Arnold, 1903, California Acad. Sci. Mem., vol. 3, pp. 90, 91. 

 Strongylocentrotus purpuratus Stefanini, 1911, Soc. geol. italiana Boll., vol. 30, p. 707. 



~Description. — Arnold, who mentions the discovery of spines of this species in the Cali-- 

 fornia Pleistocene, says: 



Numerous spines of this small purple sea urchin have been found in the San Pedro series. No part of the test 

 has ever been discovered in these deposits, to the writer's knowledge. Several nearly perfect tests of this species were 

 found in the Pleistocene (lower San Pedro series) deposits at the bathhouse, Santa Barbara. A nearly perfect test 

 was also found in the upper horizon of the San Diego formation (Pleistocene (?) ) at Pacific Beach, near San Diego. 



Localities. — San Pedro, Santa Barbara, and San Diego, Cal. 



Geologic horizon. — San Diego formation (upper part), Pliocene; San Pedro formation 

 (lower part), Pleistocene. 



Collection. — Leland Stanford Junior University. 



Subclass IKREGULARIA. 



Order GNATHOSTOMATA. 



Silborder CLYPEASTRINA. 



Family SCUTELLID.E. 



Dendraster excentricus (Eschscholtz) . 



Plate CIV, figures la-d; Plate CV, figures la-d. 



Scutclla striatula De Serres, 1829, Geognosie ten-, tert. du midi de France, p. 156. 



Scutella excentrica Eschscholtz, 1831, Zool. atlas, p. 19,P1. XX, figs. 2, 2a, 2b. 



Echinarachnius excentricus Valenciennes, 1846, Voyage Venus, Zooph., PI. X. 



Dendraster excentricus L. Agassiz, 1847, Cat. raisonne des echinodermes, Soc. Nat. Ann., vol. 7, p. 135. 



Dendraster excentricus Gray, 1855, Cat. Recent echinoderms, p. 16. 



Dendraster excentricus Stimpson, 1857, Boston Soc. Nat. Hist. Jour., vol. 6, pp. 526-527. 



