40 BI'LLETIN 76, UNITED STATES NATIONAL MUSEUM. 



clmnu-tcr to those of L. ardicus, but slightly larger, and spinelets a trifle longer, 

 Base of pedicel llarmg into a roundish plate with four or five short, rather irregular, 

 lobes by wliich the plates touch or imbricate slightly, and between which the 

 pupuhe emerge. Larger paxilla; with about twenty-five peripheral and tliirty 

 central slender delicate terete blunt spmelets; spinelets occupying center of tabulum 

 form a coordinate llut-topped group, usually stand upright, and are crowded; 

 peripheral spinelets usually radiate and are not equal in length. 



Abactuial plates, in a prepared specmien, from uiner or coelomic side: Plates 

 ratlier small and dose-set irregularly stellate with short irregular lobes by which the 

 plates overlap. Papulae absent from a narrow radial line, interrupted on the 

 interradial line, and absent from a circular area (with radius about 0.4 r) in center 

 of disk. On the radial line the plates are more crowded, and are without regularity 

 as to the number of lobes and in arrangement. The plates are also variable in 

 size and more uneven m contour than those on the papular areas. The plates 

 on the central nonpapular area of disk are small, roundish, and crowded, with a 

 number of larger scalloped or irregularly incised plates scattered here and there. 

 On the papular areas the plates are arranged in transverse rows parallel with inter- 

 radial line, but the regularity is frequently interrupted. Adcentrally to the mad- 

 reporic canal is a large tumid plate, rounded on the outer side and angular toward 

 the canal. On either side are two smaller more elongate plates, while a small plate 

 completes the circle on the outer side. 



Marginal plates short, band-like, but both series more conspicuous than in 

 L. ardicus; superomarginal plates, thirty in number, from interradial line to ex- 

 tremity of ray much wider than long on proximal half of ray, the width rapidlj' 

 decreasing on outer portion until plates are nearly c^uadrate. Plates form an 

 arched bevel to margin of abactinal area, are separated by deep fasciolar grooves, 

 and are covered with short delicate terete spinelets, which form a close nap all over 

 exposed surface. 



Inferomarginals corresponding to superomarginals, beyond which they extend 

 lateral!}', fonning the rounded margin to ray. They are separated from supero- 

 marginals b)- a rather wide groove, which is not so deep as the transverse fasciolar 

 furrows, these being deeper between inferomarginals than between superomarginals. 

 Plates short, band-like, obliquely oriented to radial line (superomarginals being 

 transversely oriented), forming a well-arched bevel to actinal surface. First plate 

 about twice as wide as corresponding superomarginal (sometimes somewhat more). 

 Ail plates densely covered mth small spinelets similar to those of superomarginals, 

 but a trifle larger, those of transver&.^ median region slightly squamiform and 

 directed outward. 



Actinal interradial areas about the same size or a trifle smaller than in L. arc- 

 ticus; one series of intennediate plates extending about three-fourths length of ray 

 or to eighteenth inferomarginal ; a second series extending to seventh or eighth 

 plate, and a third series confined to angle bounded by adjacent first two plates. 

 Intermediate plates with a low tabulum crowned by a coordinate group of fifteen or 

 twenty papilliform spinelets, those in center being slightly thicker and more clavate 

 than the peripheral ones. 



