198 



lateral corners somewhat rounded ; length to breadth, 1 : 2.5. 

 Further out on arm, the plates, as is usual in the genus, grow 

 smaller and smaller, from being encroached on by the side arm- 

 plates. Upper arm-plates much broader than long, and having 

 the outer and inner sides straight and parallel ; length to breadth, 

 near base of arm, 1.2 : 3.5. Scales of disc, above and below, not 

 arched or swelled, but lying very flat and evenly ; primary plates 

 rounded, and conspicuous by their size. Notches in disc, at base 

 of arms, deep, admitting fully four arm-plates. Comb on the 

 edges of each notch made up of thick, flat, spreading papillae, 

 crowded side by side, in a continuous line. These papillae are 

 only 6 or 7 ; they decrease in length as they pass under the disc, 

 where they join the narrow, toothed edge that runs along the mar- 

 gin of each genital slit. On base of arm proper, no comb, or line 

 of papillae. Arm-spines 3, tapering, sharp ; upper one longest, 

 and equal to about 1^ joints ; lowest one shortest, and equal to a 

 little less than one joint. Tentacle-scales of innermost pair of pores 

 short, stout, crowded, flattened ; usually 4 or 5 on outer side, and 4, 

 somewhat smaller, on inner side, of each pore. Rest of tentacles 

 with only one round and rather thick scale, but there may also be 

 a little tooth, just outside the tentacle. Color, in alcohol : above^ 

 bluish gray, (a sort of clay-color,) with darker markings ; the 

 arms the same, with darker bands ; below, arms whitish ; inter- 

 brachial spaces of a purplish hue, with white spots. 



This species is nearest 0. Sarsii, but differs in the want of a 

 row of papillas on the base of the arm, above ; in having the pa- 

 pillae of the arm-comb and of the inner pair of tentacle-pores 

 more crowded and blunter ; in the finer and sharper mouth- 

 papillce, &c. 



Locality, Puget Sound. Dr. Kennerly. 



Smithsonian Institution, No. 1039. 



There are also, in the Smithsonian collection, specimens from 

 Puget Sound, which closely resemble the young of 0. Sarsii ; 

 but, as they are not very well preserved, they must remain for 

 the present in doubt.- 



Ofhiura, (Lamk. non Forbes.) 

 Ophioderma, (Miill. & Trosch.) Ophiura teres, (Lyman,) sp. nov. 

 Description of a Specimen. Diameter of disc, 32 millim. 



