ASTEROIDEA OF NORTH PACIFIC AND AWACENT WATERS KISIIER. 383 



papilla as in tho lulult, but without any sacculus at the tip. Tiir> niar(,nna! mouth 

 spinos are vtuiahlo, lanfiinij from three to five in number and <iifT('rin<; also some- 

 what in relative position. The innermost is abruptly larj^er and usually somewhat 

 spaced from the laterals. It appears to be a suboral moved to a marfrinal [H)sition. 

 The longest adambulaeral spinelet sometimes has a short sacculus. The smallest 

 specimens are essentially like the above except that it is increasingly difTicuit to 

 make out spiracula. 



This series of young indicates that the nunibcr <>f ndambulacnil spines, number 

 of paxillar spines, number of rows of jiaxillie along ray, and number of mouth 

 spines do not differ to any important extent with age, but that the s|Mraeula 

 increase greatly with age, and integumentary appendages of spines also ap|>ear 

 in older specimens, when the young do not i)os.sess them. The interbrachial webs 

 increase with age and probably the S|)eeial spiracular areas do not appear fifl the 

 animal is nearly adult. 



Type.— Cat. No. 2'2344, I'.S.X.M. 



Type-locality. — Albatross station 4I5S7, off San Diego, California, (longitude of 

 Point Conception), 1,059 fathoms, green mud; one specimen. 



Distribution. — Bering Sea to San Diego, California, and probably south to the 

 vicinity of Panama, 1,059 to 1,771 fathoms, mud and ooze. 



Specimen.<i examined. — Fifteen; besides tho t^vpe, nine from station 2S59, off 

 Prince of Wales Island, Alaska, 1,5G9 fathoms, gray ooze; five from station 3603, 

 Bering Sea, between the Pribilof Islands and l^nimak Island (Aleutians), 1,771 

 fathoms, blue ooze. 



liemarks. — There is a possibility that the Alaskan specimens may constitute a 

 separate race. The lack of fully grown examples from the type-locality leaves the 

 question open. However, the only difference is the greater number of spiracula 

 in the Bering Sea examples. This character, as the specimens prove, varies greatly 

 with age, and immature Alaskan examples are not essentially different from the 

 t\-pe. 



The foregoing description is an attempt to describe the species rather than a 

 single specimen. The description of the immature type was given when the species 

 was named, but this is incomplete for the species, and has acconiingly been emen<led. 



The very' considerable inimber (four or five) of adambulaeral spinelets sepa- 

 rates this species from most others of the genus, placing it in section D of Slailon's 

 Synopsis (1S.S9, p. 494). It differs from //. coccinatitu in the form of the adam- 

 bulaeral comb (compare figure with Challenger Asteroidea. pi. 91, fig. 12), lack of 

 distinct muscular reticulations in supradorsal membrane, in having many more 

 spiracula (as many as in //. porosissimu^s), in having a less widely expanded pair 

 of mouth plates (and different armature), and in having an interbrachial and 

 lateral muscular web. The abactinal muscular reticulations of tocrinatus are very- 

 conspicuous, although tho typo is probably young. //. i]uatlri.<<pinosux differs 

 from //. prxcoquis" in having fewer paxillar spinelets, a paxillar area well differ- 

 ent iateil fnun a lateral web, more mimerous spiracula, and large and ilifferently 

 formed aperture papilla?. The aperture papilla- of prxcoqxiin are ver>' like those of 



a See Sladen I'hallmgcr Asteroidea. 1889, p. 524, pi. 90, fipt. 5, 6; pi. 91, fign. 1»-15. 



