ASTEKOIDEA OF ^■OKTH PACIFIC AND ;U)JACENT WATERS — FISHER. 281 



the glassy tip is sharper and less conspicuous. The doi-so-luteial plute.s arc fre- 

 quently in fairly regular vertical rows, each correspomling to a stiperomarginal; 

 in the interspace hetween them are smaller secondary plates. These rows are more 

 regular in the hidividuals with gla.ssy spinelets. and the presence of the smaller 

 intermediate plates may bo another indication uf advanced age. 



There arc three regidar rows of conspicuously large, regular plates adjacent to 

 the adambulacrals. The middle row (the inferomarginal) has tiie largest plates. 

 Usually the upper or superomarginal series has slightiy smaller plates, while tiiose 

 of the actinal series, adjacent to the adaml)idacrals, are smallest. A regular row 

 of mostly single pai)ulje runs between these series, although that between llie actinal 

 and adambulacral series does not extend far along the ray except in old examples. 

 The intra-marginal ])lates at base of raj- do not extend far along ray (about two- 

 thirds of r, measuretl from interbrachial line). 



Adambulacral spinelets variable in number but usually eight to twelve, in the 

 form with glassy spinelets, and twelve to eighteen in the other variety. In the 

 former there are tj'pically two transvei-se rows, with one or two enlarged furrow 

 spinelets (two in an oblique series, or one median and two in a longitudinal row 

 just back of it). In the variety with slender, niultidenticulate spinelets there are 

 usually three transvei-se rows of spinelets to each adambulacral ])late, and two or 

 three furrow spinelets. Intermediate specimens, in respect to the adambulacral 

 armature, are several of the second variety with the armature characteristic of the 

 fii-st. As usual in Ilenricia, there is a curved spinelet on the furrow face of each 

 adambulacral plate. Madreporic body covered with spinelets and with coarse 

 irregular radiating striae. 



Color in life, bright brick red, orange on actinal surface; specimens collected 

 by Dr. J. C. Brown at Port Renfrew, British Columbia, were as above; some small 

 thick-armed examples had slate-gray to lilac or drab disks with the same colors 

 running out upon arms. In other sjiecimens there was a yellowish brown color 

 instead of red as a backgrouml, with here and there invasions of brick red on the 

 disk and arms. Specimens from Monterey Bay vary greatly in color, for wliich 

 see below, "Specimens from Monterey Bay." 



Variations. — The littoral form from Puget Sound with very regular marginal 

 plates, eight to fifteen adambulacral spinelets, and the abactinal spinelets ending 

 in numerous sharp denticulations rather than in a solid glassy tip, is assumed to be 

 the typical one. This conclusion is based on an examination of a specimen evi- 

 dently labeled by Stimpson. Tiie type is therefore one of the various forms of 

 variety B, among tho.se listed herewith. 



Variety A. — This form varies in tlie lengtii and breadth of tlie rays. The 

 thick-armed examples are usually small, while the meilium and slender-armed ones 

 are much in the majority. I take Doctor Clark's Ilenricia hviuscula cras.ta and 

 II. I. atletniala to be variations in proportions of this and the following form, as no 

 differences other than the shape of rays and size of disk arc given. Monterey Bay 

 to Kailiak Island. There is less variability in the spmulation of this than of any 

 other variety. (PI. G9, fig. 1; PI. 70, figs. 1, 2rt.) 



Variety B. — This is the second variety noted in the foregoing description. 

 The principal differences are in the slenderer and niultidenticulate spinelets. more 



