92 BULLETIN 76, UNITED STATES NATIONAL MUSEUM 



The specimen, which is labeled as from station 3350, 75 fathoms, differs from the 

 typical form in having 20 rays, usually 2 inferomarginal spines, numerous adambula- 

 cral straight pedicellariae, rather more numerous abactinal straight pedicellariae, 

 and less numerous abactinal disk spines. The specimen from station 3349, 239 fath- 

 oms, has two inferomarginal spines on a few of the plates, but has fewer adambulacral 

 pedicellariae (possibly scraped off some of the rays, as they are numerous on 

 others). Both specimens have lost through abrasion a number of thin abactinal 

 spines. These two examples seem to represent an incipient northern race. I do not 

 feel sure of the correctness of the label on the specimen from station 3350. It 

 resembles so closely in color and texture, as well as in certain individual peculiarities 

 that from the preceding station, that I believe there is a possibility of mistake. 

 Seventy-five fathoms is abnormally shallow for this species. The same reasonable 

 doubt attaches to the record from station 4340. 



Anatomical notes. — The coelom of the disk is almost entirely occupied by the 

 large eversible stomach the lobes of which, very much wrinkled, reach to the base 

 of the rays. When the stomach is entirely withdrawn and in normal position, the 

 dorsal division, into which the hepatic coeca empty, can be clearly differentiated. 

 Its periphery is about 0.4 the distance from the center to edge of disk. There is a 

 well-marked constriction between this dorsal division and the ventral eversible 

 stomach. The hepatic coeca depart from the dorsal stomach as a single wide duct, 

 attached to the wall of the ventral stomach by a net-like mesentery. After passing 

 through the constricted entrance to the radial coelom, the duct divides in two and 

 extends about 0.8 the length of ray. Each duct is differentiated into numerous lateral 

 unequal lobulate saccules arranged pinnately with reference to the central tube, 

 which is fastened to the dorsolateral wall by a thin mesentery. Dorsal to the upper 

 stomach is an intestinal coecum, rather acutely elliptical in form, about 10 mm. long 

 and 4 or 5 mm. in diameter. It has a delicately plicated interior, and at the inner 

 end has a conspicuous opening into the dorsal stomach and a small aperture leading 

 into a very insignificant intestine. 



The interbrachial septum is a tough membrane of small size. The inner free 

 edge reaches mesad nearly as far as the inner border of the actinostomial ring, while 

 the outer interbrachial edge, which is fused with the wall of the disk at the inter- 

 brachial angle, is opposite the eighth ambulacral plate. There is no rudiment what- 

 ever of a horizontal shelf projecting from the inner border of the actinostome above 

 the first ambulacral plates and then distad into the ray, as in the case of Heliaster. 

 (Such a shelf forms a coelomic cul-de-sac just above the ambulacral ridge and ventral 

 to the hepatic coeca, and is an anatomical peculiarity of Heliaster.) 



The gonads open upon the side of the ray about 1.5 r from the interbrachial 

 angle, and slightly above the level of the superomarginal plates. One lobulate branch 

 extends distad CO mm. and another toward the base of ray about 10 or 12 mm. The 

 short lobes of the branches are subdivided into small secondary lobes or divisions. 



Ampullae large, single. They form two series along each side of the ambulacral 

 ridge, but the pores between the ambulacral plates form a single series, fairly straight 

 in small specimens and slightly zigzag in large ones. No Polian vesicles. 



Type.— Cat. No. 21934, U.S.N.M. 



Type-locality.— Station 2925, off San Diego, Calif.; 339 fathoms, mud; bottom 

 temperature, 42.9° F. 



