1913.] Clark, Echinoderms from Lower California. 187 



ASTEROIDEA. 



Eremicaster tenebrarius. 



Porcellanaster (Eremicaster) tenebrarius FISHER, 1905. Bull. Bur. Fish., Vol. 24, 

 p. 293. 



Eremicaster tenebrarius LUDWIG, 1907. Zool. Anz., Vol. 31. p. 318. 



There is a single speeimen of this species in the collection. It has R : 

 25 mm. and r = 8 mm. Each of the superomarginals carries a conspicuous 

 spine. There is only a single furrow spinelet on each adambulaeral plate, 

 but the segmental papillae are conspicuous nearly to the end of the arm. 

 The terminal plate has only three spinelets. There are hut ten supero- 

 marginal plates. In all these points, this individual resembles Alaskan 

 specimens more closely than it does those from California. 



Station 5(5X4. Southwest of Santa Margarita Island, west coast of 

 Lower California, 1700 fms. 



Eremicaster pacificus. 



Porcellanaster pacificus LUDWIG, 1905. Mem. M. C. Z., Vol. 32, p 89. 

 Eremicaster pacificus FISHER, 1907. Zool. Anz., Vol. 32, p. 14. 



Both adults and young are represented in this series, the largest having 

 R = 24 and the smallest, R == 8. As the latter is considerably smaller 

 than any hitherto described, a few details of its structure may be worth 

 recording. There are eight or nine adambulaeral plates but only five or six 

 marginals. Most of the supermarginal plates carry a spine and the adam- 

 bulacrals usually have two, but the distal ones may have only one. The 

 terminal plate of each arm carries five spines, of which the median is 1^ mm. 

 long. The median cribriform organ is made up of eight to ten lamellae 

 but the lateral ones are much less developed and have only four to six 

 lamella?. The madreporite is large and the periproctal tube is 1\ mm. long. 



Station 5073. Off Ft. San Tomas, west coast of Lower California, 

 1090 fms. 



Station 5091. Off Pt. San Tomas, west coast of Lower California, 

 80S fms. Bottom Temp., :-!7.2 . 



Station 5092. Off Pt. San Tomas, west coast of Lower California, 

 1070 fms. Bottom Temp., 37.1. 



Eleven specimens. 



