NEW STARFISHES FROM DEEP WATKR OFF CALIFORNIA AND ALASKA. 'MM 



to the extremity; these spines seem to increase in size toward the inner angle, where there are 6 

 teeth, larger and heavier. General surface ..t plates covered with small papilliform spinelets similar 

 to those i if actinal intermediate plates, these increasing in size ami thickness at inner angle 



Actinal interrailial areas small, the intermediate plates, which are slightly convex, extending to 

 the sixtli nr seventh inferomarginal, those adjacent to the adambulacral plates being largest; plates 

 armed with spaced, radiating, small, papilliform spinelets. In a smaller specimen than the type 

 several plates of each area hear a peculiar pedicellarian apparatus consisting of 3 or 4 shorter, thick- 

 ened, clavate spinelets closely appressed. In the type there are but 1 or 2 to each area. 



Madreporic body large, 8 mm. in diameter, situated a little mine than half its own diameter 

 distant from margin, and hidden by -lit large innate paxillse, which stand Hush with the general 

 surface: these paxillse are larger than any on the general abactinal surface and their spinelets are 

 heavier and more clavate, those situated on the periphery being slenderer, however, and apparently 

 mucronate. 



Locality: Station 4.^)7, off San Diego, Cal., 2,196-2,228 Ems., gray mud. 



This is apparently a very distinct species related to Dytaster • n/ix Sladen, from which it differs in 

 having shorter and broader rays, the sides of which are curiously arched inward on the distal portion; 

 less crowded paxillse which have a greater number of spinelets; more numerous marginal plates, the 

 ventral series of which do nut encroach upon the actinal area to any great extent, and a rather less 

 numerous series of furrow spinelets, which further differ in form. 



This species is named for Dr. Charles Henry Gilbert, professor of zoology in Stanford University. 



Subfamily MIM ASTKIIIN.F. Sladen, 1889. 



Genus MIMASTER Sladen. 



ffimaster Sladen, Proc. Roy. Soc. Edin. XI, 18S2, 702; Trans. Roj Soc. Edin XXX [1)1882,579 U tizardi Sladen.) 



Mimaster swifti, new species. 



Rays 5. R = 114mm.; r=43 mm, R=2.65r. Breadth of ray al base, between first and second 

 superomarginals, 50 mm. 



General form large and robust, much flattened; rays broad al base, tapering evenlj to a bluntly 

 pointed extremity which is upturned; interbrachial arcs wide, rounded, but subangular, rather more 

 rounded than in .1/. cognatus; abactinal surface slightly inflated, sunken in interradial anas: actinal 

 surface slightly convex on rays, evidently capable of inflation, especially in actinal interradial areas; 

 marginal plates conspicuous; no pedicellarise. 



Abactinal area more depressed than in either tizardi or cognatus, and covered with robust, round- 

 ish, or subhexagonal, uniform, rather closely placed paxilhe, which are arranged in transverse oblique 

 rows at the sides on the proximal portion of rays, hut are without order on distal half and on central 

 portion Of disk; paxilla- also forming longitudinal rows on basal portion of rays and largest on radial 

 anas; each consisting of a low stout pedicel expanded at both ends, the summit surmounted by a 

 nearly flap-topped group of about 25 short, robust, round subclavate, granuliform spinelets, those in 

 the center occasionally Hat-topped, hut usually like the rest, round-tipped; in addition to these about 2 

 irregular peripheral series of very much smaller lanceolate subpetaloid spinelets placed lower down 

 on the pedicel ami ap pressed closely to bases of outer minis! spinelets, so that they arc not usually 

 superficially visible; papula- very numerous, arranged irregularly about the pedicels 



Marginal plates fairly conspicuous, but partaking of the nature of very large paxilhe; a well- 

 defined, narrow, naked groove between superomarginals and abactinal paxilla-; both series with 

 especial raised ridges, crowned with coarse granuliform spinelets, which increase in size toward center 

 of ridge, when- they are quite heavy and similar to very much enlarged spinelets of tin- paxilhe, 

 though more tubercular and pointed; on inferomarginals the spinelets arc still thicker and heavier 

 and increase in size toward actinal end of plate; super arginals, 40-4M in number from median inter- 

 radial line to extremity of ray, much wider than long and st prominent at middle of ray, where 



the furrows between them are wider than elsewhere; tiny encroach upon the abactinal ana, forming 

 a well-defined border; inferomarginals corresponding to tin- dorsal series, ami between the 2 series a 

 fairly prominent groove; between inferomarginal spinelets and actinal intermediate plates another 

 groove, for the most part obscured. 



