﻿OPIIIUKA IIOLMESir. 21 



Ophiura Holmesii Lyman. (P1. I., Fig. 7.) 



Ophioderma variegalum Agass. MS. 



Ophiura Holmesii Lyman ; Pi-oceed. Boston Soc. Nat. Ilist., VIL p. 255. 18G0. 



Sjiecial 3Iarks. — Disk thick; arms stout, stiff; in length less than 

 four times diameter of disk. Color, various patterns of white, and of 

 different shades of green. No naked scales at base of arms. 



Description of an Indivichcal — Diameter of disk, 19.2°""- ; from outer 

 side of mouth-shield to outer corner of opposite mouth-slits, 7.4"""'' ; 

 greatest width of arm without spines, 4.4""-; length of arm, about 74"""'; 

 distance from outer edge of mouth-shield to inner points of mouth- 

 papilltB, to that between outer corners of mouth-slits, 2.8 : 4.2""°-. Mouth- 

 papilla3 small, stout, rounded, pointed ; from 16 to 18 ; outermost one 

 somewhat longer than rest ; one next to outermost, broad and flattened ; 

 two mnermost pointing to centre, and somewhat longer than those near 

 them. Teeth, four in number ; uppermost one longer than others, flat, 

 and sharp-pointed ; three lower ones thin, flat, and with a rounded, cut- 

 ting edge. Mouth-shields long heart-shaped, with point inward ; on 

 outer edge a slight indentation ; length to breadth, 1.8 r 1.6""- ; madre- 

 poric shield shorter and broader, and with a small depression near outer 

 edge. Side mouth-shields small, rounded, thickened, varying somewhat 

 in shape, but commonly shorty rounded, triangular ; length to breadth, 

 1.2 : l™"-; length to that of mouth-shields, 1.2 : 1.8""°. Under arm-plates 

 squarish ; outer side curved, laterals a little re-enteringly curved, inner 

 side and inner laterals short, of about equal length, and lying almost in 

 one line ; farther out on arm, inner laterals and inner side are very 

 decidedly inclined to each other, and the curve of outer side is broken 

 up into an outer side and two outer laterals, so that here the plates 

 have the form of a nearly regular octagon ; between first and second 

 plates, and second and third plates, a pair of pores, separated by a little 

 tooth. First plate very irregular oval, with a notch on its mner side ; 

 length to breadth, .8 : 1.4°""-. Second plate with a curved outer side, 

 lateral and inner sides re-enteringly curved, the latter most so ; length 

 to breadth, 1 : l.l"""-. Third plate, outer and inner sides curved, the 

 latter the less ; lateral sides re-enteringly curved ; length to breadth, 

 1.2 : 1.6""°-. Fifth plate, same as third ; about one third out on arm, 

 plates octagonal, length to breadth, 1.2 : 1.4 ; near point of arm heart- 

 shaped, with point inward. Side arm-plates compactly soldered with 

 surrounding parts, stout, a little overlapped by upper plates, their outer 

 edges showing plamly, by reason of shortness of arm-spines ; they con- 

 tinue till quite near end of arm wdthout meeting either above or below. 

 Upper arm-plates much broader than long, outer corners rounded, inner 



