54 BULLETIN 76, UNITED STATES NATIONAL MUSEUM. 



tlic species probal)lv has a continuous distribution by way of Bering Sea. It is 

 of interest to note "that the Japanese examples are fairly typical. Both of them 

 have epiproctal cones, and in one the liny anal i)ore is visible (in sunlight) with a 

 strong glass. 



LEPTYCHASTER PROPINQUUS Fisher. 

 PI. 9, fis. 3. 

 Leplychastcr propinqiius Fisher, ZooI. .Vnz., vol. 35, March 29, 1910, p. 545. 

 Diagnosis. — Similar in general form to L. anomalus, but with narrower and 

 more numerous marginal plates, less massive margin to disk, and smaller paxillae. 

 R = 29 mm.; r= 15 mm.; R= 1.93 r. Width of ray at base, 17.5 mm. 



Description. — This form is obviously such a close relative of anomalus that 

 the description will be largely a comparison \vith that .species. Paxillae arranged 

 as in anomalus, but smaller and less compactly placed, and with longer spinelets. 

 The pa.xillar area has the apj)carance of being more open and the outlines of the 

 paxillje are less well defined. While a large paxilla of anomalus has forty to forty- 

 five spinelets, a similarly placed one in propinquus has but about twenty-five, the 

 peripheral series containing about fifteen. The spinelets themselves are longer 

 than in anomalus, especially the centrally situated ones. Distribution of papulae 

 and form of abactinal plates practically the same as in anomalus. Plates sliow a 

 slight irregular lobing in some specimens; in others, none at all. 



Supcromarginal plates are nearly quadrate, except in interbrachial angle, 

 where the witlth is slightly greater than length, and they are only one-half or 

 slightly over one-half as wide as in equal sized specimens of anomalus, thus appear- 

 ing more typical of the genus Leptiichaster. The superomarginals are, moreover, 

 more uniform in width throughout the ray than in anomalus. Superomarginals, 

 twenty-one in number; in tyi>c of anomalus, which is practically equal sized, 

 fifteen. Spinelets covering marginals similar to those of anomalus, but, as in the 

 case of paxillae, a trifle longer. 



Infcromarginals shorter and narrower than in anomalus, coiTesponding in 

 number and i)osition to superomarginals, the covering being a trifle but not much 

 longer than in arwmalus. As compared with arcticus the infcromarginals encroach 

 more onto actinal surface and are placed less obliquely to transverse axis or plane 

 of raj'. (The form bears no particular resemblance to pacificus, tliis species having 

 large superomarginals.) 



Adarabulacral plates and spinulation not differing materially from anomalus. 

 Furrow spinelets three or four, generally three; usually four in anamalus. The 

 spinelets on actinal surface of plate are very similar if not identical in arrangement 

 with those of anomalus, but are a trifle longer. Actinal interradial areas vary 

 slightly in size and the paxilla are a trifle smaller, and the spinelets shghtly longer 

 and slenderer than in anomalus. The mouth plates and armature do not differ 

 in any important respect from those of anomalus. 



Fariah'on-s.— The essential features which distinguish this species are well 

 markeil in all of the fifty-seven specimens, and there is very little variation of 

 consequence. In other words, all have small paxilla) and numerous and narrower 

 marginal plates. The smaller specimens naturally have shorter rays, and there is 

 a slight variation in the width of the superomarginals ami infcromarginals. 



