NO. 1807. A NEW GENUS OF STARFISHES— FISHER. 663 



Adambulacral plates nearly square, slightly larger than adjacent 

 actinal intermediate plates. The actinal surface is slightly raised for 

 the articulation of a roundish or squarish paxilliform group of numer- 

 ous delicate spinelets which increase in thickness, but not in length, 

 toward the furrow. The furrow series consists of three or four stUl 

 longer basally webbed spinelets, which reach nearly across the narrow 

 groove and wliich are sUghtly longer than width of plate. The cen- 

 tral one or two of these spinelets is slightly the longest. The outer 

 subambulacral spinelets are similar in character to the actinal inter- 

 mediate spinelets, except that the two or three prongs are longer, the 

 whole spinelet being about 0.75 mm. long. Toward the furrow, 

 however, the spinelets become thicker and end in five or six short 

 thorns, and the shaft is perforated by several longitudinal series of 

 pores, forming the characteristic reticulum; only the little prongs are 

 clear. In contrast to the abactinal spicules these spinelets are 0.1 

 mm. thick at base and 0.06 mm. at tip. The subambulacral spine- 

 lets on at least two series adjacent to furrow are basally webbed. 



Mouth plates with a dense triangular group of numerous spinelets 

 on actinal surface, the two groups on companion plates being sepa- 

 rated by a prominent median suture. Marginal spinelets about seven, 

 similar to those of adambulacral plates. 



Madreporic body small, nearly hidden by overlapping paxillae; 

 strise coarse and irregular. Anal aperture, subcentral. 



Color in alcohol, bleached yellowish brown. 



Anatomical notes. — Tube feet with strong sucking disks; no de- 

 posits. Ampullse single, incipiently two-lobed. Gonads interradial. 

 Interbrachial septa strongly calcified. Integumentary layer beneath 

 plates, tliick and tough. No superambulacral plates present, the 

 lower end of each ambulacral ossicle being, instead, produced into a 

 short lobe. Strong retractors of stomach present. 



Variations. — The cotype has somewhat slenderer rays. The mar- 

 ginal plates do not form quite such regular series as in the type, and 

 there are much fewer actinal intermediate plates. The series adja- 

 cent to the adambulacral plates extends only half the length of ray 

 or even less; the second series is one-tliird as long as the first; the 

 third, very short (only about half a dozen plates) ; the fourth is either 

 absent or represented by only two or three plates ; in one interradius 

 the fifth is just starting (one or two plates). 



Tyjje.—C&t. No. 27674, U. S. N. M. 



Tyye-locality. — Albatross station 3863, Pailolo Channel, between 

 Molokai and Maui Islands, Hawaiian Islands, 127 to 154 fathoms, 

 broken coral, coarse gravel, rocks; two specimens. 



