302 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



Superomarginals 31 or 32 in number, rather narrow, forming a 

 bevel in the interbrachia, and sloping slightly on the basal part of 

 ray, the border of the ray being gradually rounded and the lateral 

 face of plate low and not sharply marked off from the dorsal. Ex- 

 treme width of first plate equal to or slightly more than length 

 (about twice length measured along inner margin of plate in L. acti- 

 nometra) ; extreme width of fifth plate (meeting medially its fellow) 

 equal to length of fifth and sixth, measured on ambitus (in L. acti- 

 nometra corresponding plate equal to nearly 3 plates). Superomarg- 

 inals of L. actinometra all wider than long, but in L. penichra a 

 variable number on outer part of ray slightly longer than wide, and 

 all along ray the plates are narrower than in actinometra. Pedicel- 

 lariae few. The distal third or half of the ray lacks granules on 

 the transverse margins of plate; and also to a variable extent the 

 granules are absent along the median suture and outer margin. (In 

 L. actinometra the last few plates only may lack marginal granules 

 on all but the outer margin.) Terminal plate slightly wider than 

 long, or as wide as long, tubercular, with an obtuse extremity. 



Inferomarginals narrow, except interbrachially, and extending 

 laterally a trifle beyond superomarginals. They are as wide as long, 

 or a little wider than long, up to the fifth or sixth. The specimen 

 from station 5510 has shorter plates, so that the length does not 

 equal width until the middle of ray, or beyond. At middle of ray 

 17 or 18 adambulacrals correspond to 10 inferomarginals. Pedicel- 

 lariae scattered along both ventral and lateral surfaces of plates, 

 very variable in number, and usually few. 



Actinal intermediate areas as in L. actinometra^ but the pedicel- 

 lariae fewer and relatively larger. There are about 6 chevrons of 

 plates, but with the exception of those adjacent to adambulacrals they 

 are rather irregularly arranged. 



Adambulachral plates longer than wide, with angular furrow mar- 

 gin (except first 3 to 5 plates), the aboral facet of the apophysis con- 

 cave and slightly longer than the adoral, which is slightly convex. 

 Furrow spinelets 5 to 7 on the first few plates, increasing to 9 or 10 

 farther along ray, the mesial spinelets compressed, prismatic, blunt, 

 the laterals broader. The 2 aboral members are the broadest, and 

 have a blunt lanceolate contour, and serve, with the adjacent enlarged 

 ndoral spinelet of the succeeding plate, as an opercular covering for 

 the tube feet. In the type there is a distinct interval without spine- 

 lets on the aboral facet of the apophysis, the 1 or 2 distalmost spine- 

 lets of the series being separated from the rest. Near the center of 

 plate is a pedicellaria, with 2 or 3 broadly spatiilate jaws, becoming 

 narrow on outer part of ray. Outer margin of plate, with 5 or 

 convex granules larger than those of intermediate areas; and 2 or 3 

 form a series with the pedicellaria. Whenever the pedicellaria is 



