ASTEROIDEA OF NORTH PACIFIC AND AOJACKNT WATERJJ FlrillER. 349 



Type.— Cat. No. 27790 U.S.X.M. 



TrjiH'-hcality. — Albatross station 4427. (dF Saiitu ("riiz Islninl, Culiforniu, 447 

 to 510 fathoms, black mini, rocks. 



Distribution. — Known only from tyjic-locality. 



Specimen examined. — The type. 



Remarls. — This sppcios, which stands abf)ut halfway between those which are 

 stellate and those which are more or less ])enta<;onal, bears superficially more resem- 

 blance to militaris than to any other form, especially as there arc spiny often 

 fenestrated calcareous bodies in the supradorsal membrane. The differences are 

 important, however. In trigonodon the stalk of each paxilla is high (not low) and 

 crownied by six (not three to five) spines shorter than pedicel; supradorsal mem- 

 brane is thin in trigonodon, and the deposits are not so crow<Ied. The adambulacral 

 and marginal mouth spines are fewer (five, not six to eight), and the suboral spine 

 is very large ami of a special three-edged form, not cylindrical, as in niililnris. 



PTERASTER GRACIUS (Clark). 



Retasler gracHii Clark, Proc. Baston Sor. Nat. Hist., vol. 29, No. 15, May. 1901. p. S'Jfi, pi. 3, fips. 

 Sand 4. 



The status of this species is somewhat douiitful. The two specimens are 

 probably yoimg, and, coming as they do from Puget Sound, migiit be considered 

 as immature tesselatus. This form, however, differs from \-oung tesselntus in having 

 a very thin and delicate supradorsal membrane, longer rays (R = 2 r), and only 

 two oral spines. The spiracida are fewer. 



Diagnosis. — Rays five. R = 1S mm.; r=9 mm.; R = 2 r. Breadth of ray at 

 base equals r. Disk depressed, 6 to 8 mm. high. Supradorsal membrane very 

 thin and delicate; tips of spines from the edges of the paxilla? comiected by delicate 

 lines giving abactinal surface a reticulated appearance; no spicules; spiracula 

 quite numerous, six to ten in each mesh of reticulum; ])axill£e high, with six or more 

 (often many more) spines surrounding edge, and several smaller ones erect in 

 miildle: oscular orifice small. Adambulacral plates with five webbed spines 

 arranged in a row at right angles to furrow. Of these the first is very small, the 

 second larger, the third still larger, the fourth still larger, the fifth equals the third. 

 Actinolateral spine slightly longer tiuui longest adambulacral; actinolateral mem- 

 brane with a free margin, narrow. Aperature papilhe very small, free only on one 

 side. Mouth plates prominent, each with two marginal spmes unit<>d by a mem- 

 brane, anil a very large free spine on oral surface near base, pointing downward and 

 outward. Ambulacra broad; feet comparatively few, in two rows. Color, light 

 brownish gray, darkest on tlisk, lightest near tip of rays. 



Ti/pe. — Said to have been sent to Columbia I'niversity, New York; not to l>e 

 found, 1910. 



Type-locality. — Probably Puget Sound, Washington. 



RemarliS. — This species is known only from the two specimens described by 

 Clark. Even the locality is doubtful, inasmuch as the specimens were not labeled, 

 and the collection contained several species evidently from some locality south of 

 the United States. 



