A NEW GENUS OF SEA STARS — FISHER 451 



The madreporite, 4.5 mm. in diameter, is situated at mid-r. 



There are two gonads in each ray. Each consists of a bunch of 

 branched slender lobes attached to the dorsolateral body wall 35 mm. 

 from the base of ray. 



A short pUlar of plates unites the odontophore with the abactinal 

 skeleton as an obvious support. From and including this pillar a 

 membranous septum passes interradially to the margin of disk, where 

 it again becomes fortified by a short septum of plates proceeding 

 inward from the margin. These plates are continuous with the 

 skeleton of side of ray, the lowermost elements of the septum being 

 marginal plates. 



The ambulacral plates are not particularly thin or compressed, and 

 the ambulacral pores form a straight, not zigzag, series. The tube- 

 feet, arranged in two series, are apparently fairly large and crowded 

 in the narrow ambulacral grove. The ampullae are simple, not 

 bilobed. 



Type locality. — Mutsu Bay, northern Honshu, Japan. 



Specimen described, Hokkaido, Japan, U.S.N.M. No. E. 5952. 



Distribution. — Northern Honshu and Hokkaido, Japan. 



NOTE ON THE GENUS PARASTERINA 



In the literature on sea stars there have been two quasidistinct 

 genera bearing the name Patiria. They started as follows: 



1. Patiria Gray, 1840, type P. coccinea Gray, monotypic. In 1847 

 Gray enlarged the genus to include granifera Gray, ocellijera Gray, 

 obtusa Gray, and crassa Gray. 



2. Patiria Perrier, 1875. "En adoptant ici le genre Patiria de 

 Gray nous changeons notablement les limites et la characteristiquc 

 de ce genre." Perrier discarded Gray's type, coccinea, and included 

 only ocellijera and crassa, the last obviously different from coccinea 

 and granifera. Sladen (1889, p. 384) adopted Perrier's genus, 

 omitting coccinea from the list of included species, to which ho 

 added a new one, bellula from Cape of Good Hope. 



Gray's Patiria became submerged in the more extensive Asterina 

 of Nardo, 1834. 



Perrier's Patiria was stated to differ from Asterina in having the 

 dorsal ossicles convex, nearly circular and touching one another, not 

 imbricated as is ordinarily the case in Asterina. Sladen (1889, p. 376) 

 differentiated the two groups as follows: 



Abactinal plates not imbricated; covered with spines: Patiria. 

 Abactinal plates imbricated throughout the abactinal area, or only in definite 

 regions: Asterina, Nepanthia, Disasterina. 



This seemed to be a sound distinction; and, as Patiria Perrier was 

 obviously invalidated by Patiria Gray, I renamed Perrier's group 

 Parasterina, type Patiria crassa Gray (Fisher, 1908, p. 90). 



