ASTEROIDEA OF NORTH PACIFIC AND ADJACENT WATERS — FISHER 13 



BrisingeUa there are always two gonads to each ray, and although they may be 

 branched each gonad has but a single aperture on the side of the ray at a little dis- 

 tance from the base. 7 



BrisingeUa includes the following species : B.fragilis (Fisher), B. coronata (G. O. 

 Sars), B. exilis (Fisher), B. pusiUa Fisher, B. pannychia Fisher, B. tenella (Ludwig), 

 B. monacantha H. L. Clark, and probably also the following species described by 

 Sladen: B. verticillata, B. armillata, B. discinda, and B. membranacea. Among the 

 species described by Perrier, the following belongs in this genus: B. mediterranea. 



KEY TO THE SPECIES OF BRISINGELLA HEREIN DESCRIBED 



a 1 . Costae 9 to 11, extending 4.5 r along ray, or about one-fourth total length of ray; disk platea 

 not unusually few or widely spaced; disk spinelets usually two or three to a plate; the fur- 

 row spinelet present on all plates except near end of ray; interradial plate not markedly 

 convex or keeled; dorsal end of first ambulacral ossicle about twice as long as that of the 



second exilis. 



a 2 . Costae 20 or more extending far along the ray; disk spinelets usually one to a plate; interradial 



plate markedly convex; dorsal end of first ambulacral ossicle less than twice as long as that 



of the second. 



b 1 . Disk plates unusually few, widely spaced, embryonic, with ordinarily a single tiny spinelet, 



occasionally two, to each plate; furrow spinelet absent except an adoral one on first 3 



to 14 plates pusilla. 



b 2 . Disk plates not unusually few, spaced about the length of the spinelets, which are about 

 0.5 mm. long; an adoral and an aboral furrow spinelet, extending far along ray 

 pannychia. 



BRISINGELLA EXILIS (Fisher) 



Plate 2, Figures 2, 2a— 2c; Plate 8, Figures 2, 2a, 26 



Brisinga exilis Fisher, New Starfishes from Deep Water off California and Alaska, Bull. 



Bur. Fisheries for 1904, vol. 24, June 10, 1905, p. 318. 

 BrisingeUa exilis Fisher, Ann. and Mag. Nat. Hist., ser. 8, vol. 20, 1917, p. 427. Bull. 



U. S. Nat. Mus. 100, vol. 3, 1919, p. 524. 



Diagnosis. — -Rays 10. R. 250 mm.; r 10 mm.; R = 25 r; thickness of disk, 4 

 mm. ; breadth of ray at base, 5 mm. ; at widest part of genital inflation, 6 mm. Rays 

 deciduous, delicate, long and very slender, with an attenuate lashlike outer portion; 

 costal ridges, prominent, slender, well spaced, 9 to 11, opposite alternate adambula- 

 cral plates, and extending 4.5 r along ray, or about one-fourth total length of ray; 

 lateral spines long, very fragile, opposite alternate adambulacrals; adambulacral 

 plates with one adoral furrow spinelet and 1 slender, delicate subambulacral; mouth 

 plates with one to three actinostomial spinelets, often one aboral furrow spinelet, 

 and one suboral sharp spinule; upper end of second ambulacral ossicle about half as 

 long as first and third; a movable plate at upper end of the interradial plate, the 

 latter with a flat or grooved surface. 



Description. — Disk thin with a beveled border, and not elevated above the rays 

 to any extent. Integument of disk thin and very flexible, the plates delicate, round- 

 ish, oval, elliptical, or irregular, with irregular patches of the integument between 

 them. The plates touch or are slightly separated, and bear one to five, usually two 



'Q. O.Sars: On some Remarkable Forms of Animal Life from the Great Depths off the Norwegian Coast, Chrlstianls, 1876, 

 pi. 1, flg. 12a. 



64406—28 2 



