201 



each radial shield, an irregular patch of white ; below, inter- 

 brachial spaces mottled, reddish and white ; mouth-apparatus 

 whitish ; lower arm-plates whitish, edged with pink ; other parts 

 same as upper surface, but lighter. 



Variations. A specimen of about the same size as the pre- 

 ceding, had usually three, instead of two, primary plates in each 

 brachial space on the upper surface of the disc, also a distinct line 

 of white, running quite round the disc, near its edge. A young 

 one, with a disc 3 milHm. in diameter, had arms 12.5 millim. in 

 length. The arm-spines were more slender, and were thorny, as 

 were also the spines and grains of the disc. In the centre of the 

 disc a patch of white, and another at the base of each arm. 



This species is interesting, as being the second of a genus which 

 before had but one member. It is distinguished from 0. acvleata, 

 by the close and regular granulation of the disc, without spines 

 above, and by having no primary plates in the zV^^erbrachial 

 spaces. It seems, also, to be a much smaller species. 



Locality, Puget Sound. Dr. Kennerly. 



Smithsonian Institution, No. 1062. 



Ophiothrix, (Mull. & Trosch.) 

 Ophiothrix lineata^ (Lyman,) sp. no v. 

 Description of a Specimen. Diameter of disc, 10 millim. 

 From outer edge of mouth-shield to outer corner of opposite 

 mouth-slit, 4.5 millim. Width of arm, without spines, 2 mil- 

 hm. Length of arm, 63 millim. Tooth-papillae fine, numer- 

 ous, cylindrical, resembling short, blunt spines. Mouth-shields 

 broad oval, with a slight peak toward mouth ; length to breadth, 

 1 : 1.5. Disc, above, with large radial shields, which are smooth, 

 or very nearly so, shaped hke an elongated triangle, the acute 

 angle being turned inward, separated by a distinct stripe ; 

 length to breadth, 2.8 : 1.7 ; the narrow brachial and broad inter- 

 brachial spaces form ten stripes, radiating from the centre ; both 

 centre and stripes are covered with elongated scales, (only to be 

 seen on dried specimens,) and these, again, bear many little grains, 

 each with a crown of thorns ; below, interbrachial spaces quite 

 naked. Upper arm-plates broad hexagonal, with corners a little 

 rounded, the two side angles more acute than the others ; leno-th 

 to breadth, .7 : 1.5. Under arm-plates nearly oval, but with some 



