ASTEROIDEA OF NORTH PACIFIC AND ADJACENT WATERS — FISHER 



51 



papular areas big enough to contain three papulae, proxirnally. There are three 

 series of actinolateral plates proxirnally. 



Type— Cat. No. E. 1417, U.S.N.M. 



Type-locality. — Station 5694, southwest of Santa Cruz Island, Calif., 640 

 fathoms. 



Distribution. — Off southern California, from the vicinity of Santa Cruz Island to 

 Los Coronados Islands, and from about 500 to 1,100 fathoms; bottom temperature, 

 38° to 38.9° F. 



Specimens examined. — Seventy-two. 



Specimens of Myxoderma sacculation ectenes examined 



Remarks. — A species which is related to this form is Myxoderma longispinum 

 (Ludwig), 16 the type of which was dredged at station 3435, Gulf of California, 859 

 fathoms, brown mud, bottom temperature, 37.3° F. Other specimens were taken 

 east of the Galapagos Islands and from the Gulf of Panama, 782 to 1,322 fathoms. 

 The largest specimen examined by Ludwig had R 29 mm. 



I have before me a specimen from the type-locality with R equal to 28 mm. 

 I have also examined the type. All the specimens are, of course, very immature and 

 no new species should have been founded upon such young material. I have examined 

 the cotype for the superambulacral plates and find them present, the first large super- 

 ambulacral buttress being well developed. 



M. longispinum is not at all the same species as M. saccvlatum ectenes. I have 

 compared specimens side by side and the following differences are readily detected: 

 longispinum has still slenderer rays (see Ludwig, pi. 14) capped by a much smaller 

 terminal plate which has a deeper adcentral notch and is about half as broad and a 

 fourth shorter than that of ectenes. The abactinal pedicellariae are few and less than 

 half as large as those of ectenes, while the median radial plates are more carinate and 

 their spines fully twice as long as the carinal spines of ectenes. The furrow pedicellaria 

 is smaller than in ectenes. The narrowness of the outer half of ray is expecially notice- 

 able. 



" Zoroaster longispinut Ludwig, Mem. Mus. Corop. Z08I., vol. 32, July 17, 1905, p. 180, pi. 14, figs. 71-74; pi. 29, 

 figs. 109-170. 



