314 HFLLETIN OF THE BUREAU OF FISHERIES. 



angles, or a little nearer the outer; margin of each plate rounded, but somewhat angular where the 



furrow edge merges with that turned toward the ith; general form of mouth plates strongly 



recalling that of Pteraster and allied genera, the median beak on the actinostomial margin, in line of 

 the median suture, being present; armature consisting of 4 marginal spinules, that nearest the adoral 

 beak being largest, the third situated on angle between furrow and actinostomial margin at a lower 

 level in the furrow than the other spinules, and often directed across or down into the furrow, while 

 the others are reflexe.l; fourth spine commonly standing somewhat mi actinal surface; all enveloped 

 in membrane, which is prolonged beyond the tip in a sacculus. 



Actinal interradial areas very small; apparently no actinal intermediate plates. 



Madreporic body of medium size, situated about midway between center of disk and margin, 

 irregularlv circular in outline, with coarse, often branching, centrifugal ridges and narrower stria- 

 tums; anal opening somewhat eccentric, surrounded by low, cylindrical, granuliform spinelets; ambu- 

 lacra] furrows wide; actinostome not very wide, often completely closed over by mouth plates; tube 

 feet with a button-like terminal disk. 



Locality: Station 4410, between Santa Catalina and Santa Barbara islands, 17* to L95 fms., tine 

 gray sand and rocks. 



Family PTERASTERII>.£ Perrier, 1875. 



Genus PTERASTER Muller and Troschel. 

 Pteraster Muller and Troschel, System der Asteriden, 1842, rjs {Asterias mUitaris o. F. Muller). 



Pteraster jordani, new species. 



Kays 5. R = 75 mm.; r = 37 mm. R = L'r. Breadth of ray at base, :'>7— 12 nun. Thickness of ray 

 at base, about 28 mm. 



Form stellate, depressed; abactinal surface Of rays and disk convex, actinal surface subplane: 

 edges of ray rounded; rays tapering, with fairly straight sides, bluntly pointed, though sometimes 

 swollen near tip and the extreme tip recurved, giving an entirely different appearance; interbrachial 

 angles obtuse; a well developed lateral fringe present. 



Supradorsal membrane rather thin, with no deposits of calcareous matter; paxillar spines very 

 prominent; 2 spines to each paxilla I sometimes 1 or :; 1, I considerably longer than the other, protrud- 

 ing ■". or 4 nun. above general level of the membrane, but carrying the latter with it; pedicel very low . 

 and the spine correspondingly rather longer than usual in this genus; fine criss-crossing muscle fibers 

 exceedingly abundant, and the summits of the paxillar spines connected by faint muscular bands, 

 which are nearly invisible in the type specimen but show with some distinctness in a smaller example; 

 in the irregular meshes thus formed 1-:; large spiracula, these often absent; oscular orifice rather small. 



Adambulacral plates with a transverse series of :', spines and 1 spinelet, united by a web; inner 

 member of the series quite small and situated slightly aborad from the others; the next three4oro 

 times longer, and increasing slightly in size outward, united by membrane nearly to their tips, which 

 are capped by a membraneous sacculus; outer spine close to the corresponding actinolateral spine, to 

 which it is united by membrane; aperature papillse prominent, jawbone-shaped, free on the aboral 

 margin. On a smaller specimen the inner small spinelet is absent, aid in the type it is sometimes 

 absent, especially in plates beyond the middle of the ray. 



Armature of month plates consisting of a marginal series of 4 spines and spinelets, the inner long 

 and slender, the next nearly as long, and the outer L' much shorter; inner .'! united by membrane, 

 anil usually also the whole 4, but the outermost, which is shortest, sometimes standing alone; on the 

 actinal surface commonly 1 long, slender spine about the size of the inner marginal, with which it stands 

 in a linear series, directed over the outer end of the plate, this spine entirely free from the others. 



Actinolateral spines rather short, the 9th or 10th the longest; men 1 bra ne thin, and forming a lateral 

 fringe with a slightly undulating edge, the spines not protruding beyond its margin; width of membrane 

 only a trifle greater than that of furrow . 



Ambulacral furrows broad: tube feet in L' rows. 



Locality: Station 4:!54, vicinity of San Diego, Cal., ti4L' to 650 fms., green mud. 



Named for Dr. David Starr Jordan, president of Stanford University. 



