OPHIURA JANUARII. 



25 



mouth-sliields, such as are found in Ophlarachna. It would seem that 

 this species has variations similar to thcjsc of 0. longicauda. 



LIST OF SPECIMENS. 



CiitiiloRue 

 Number. 



Original Number 

 Number. I uf Spec. 



Locality. 



When 

 CoUecteJ. 



Whence obtained. 



Niiture of 

 Specimen. 



100 

 101 

 102 

 ?103 

 444 



1048 

 1193 



1 



12-f- 



Museum of Comparative Zoology. 



New TJi'dfonl, Mass. 



D.irtinoutli. 



S;i<r ILu-hor, L. L '? 



Bi'aufoi-t, N. C:. 



Beaufort, N. C. 



I\Iav, 1851. 



Smithsonian Institution. 



Old Point Comfort, Ya. 

 Beaufort, N. C. 



Wm. Stimpson. 



Alcoholic. 



Ophiura Januarii Lyman. 



Ophiodenna Januarii Lutkex. Yidensk. Meddclelsor. Jan., 1856. 

 Ophiodernui Januarii Lt'TKEX. Addit. ad Hist. Oph., p. 97. 



Sj^ecial Marks. — Arm-spines nearly as long as joints, round, slender ; 

 arms tapering, slender. Color, variegated greenish-gray, above ; below, 

 liy-lit straw-color. Side mouth-shields naked. 



Descrijjfion of a Sjjecimen. — Diameter of disk, 17"""'; from outer side 

 of mouth-shield to outer corner of opposite mouth-slit, 7.2°"" ; width of 

 arm, Avithout spines, 3.5°""* ; length of arm, 82'""'- ; distance from outer 

 side of mouth-shield to inner point of teeth, to that between outer cor- 

 ners of mouth-slits, 4 : 4. Mouth-papilla3 sixteen to eighteen, of more 

 even size than usual ; second and third flat, squarish, with rounded 

 edges ; the rest rounded, spiniform, nearly equal. Teeth five ; upper- 

 most and lowest flat and tapering, the former longer ; other three flat 

 and square. Mouth-shields short heart-shaped ; length to breadth about 

 1.7 : 2. Side mouth-shields broad, rather conspicuous, naked. Under 

 arm-plates, near base of arm, broad octagonal, with four outer corners 

 more or less rounded ; length to breadth (eighth plate), 1 : 1.5 ; (twelfth 

 plate), 1 : 1.3. First plate nearly oval, proportionately larger than 

 usual ; lengtli to l^readth, .8 : 1.3. About two thirds out on al'in, the 

 plates become nearly hexagonal, owing to encroachment of side arm- 

 plates, which may be seen very plainly, both from above and from 

 below. Upper arm-plates broader than long, bounded within and with- 

 out by straight lines ; inner side shorter ; outer corners well rounded ; 

 three or four ])lates enclosed by projections from disk, and modified in 



4 



