88 OPHIOCOMA SCOLOPENDRINA. 



flattened ; upper one longest and largest, but never swelled ; lengths to 

 that of under arm-plate, 5.5, 3.5, 2.5, 2 : 1.5, Tentacle-scales two on 

 base of arm, but a little way out o\Ay one. Color, in alcohol : above, 

 umber brown ; below, interbrachial spaces the same, the other parts 

 lighter ; some of the arm-spines ringed with lighter. 



Variations. — The same variations, as to the length of the arms, and 

 the length and stoutness of the arm-spines, exist in this wide-ranging 

 species, as in 0. er'maceus ; and the parallel is fmiher carried out by 

 the fact that the specimens from the east coast of Africa have com- 

 monly, though not always, shorter arms and stouter spines than those 

 from the Pacific Islands. The latter variety I have described as 0. 

 7)iolarls. 



The arms vary from five and a half to eight times the diameter of 

 the disk. The tooth-papillfB are commonly about nine, rarely twelve. 

 The color varies in depth ; the lightest specimens are pale bluish-gray, 

 varied with specks and marblings of white ; below, nearly white, w4th 

 brown lines round the under arm-plates. The lighter the color, the 

 more conspicuous are the dark rings round the spines. The number 

 of joints furnished with two tentacle-scales varies somewhat, often dif- 

 fering on the different arms of the same individual. A specimen with 

 a disk of 23°"°- had arms of 161""- ; length of arm-spines to under arm- 

 plate, 4.5, 4, 3, 2.5 : 1.4. A small specimen had the disk 14™™-, arms 

 110 ; arm-spines to under arm-plate, 4, 2.5, 2, 1.6 : 1.1. The original 

 Ophiura scolopendruia of Lamarck is a dried specunen, from the He de 

 France, and now in the Jardin des Plantes. The disk is 27°""' in diam- 

 eter; arm, 175™'"" long ; upper arm-spine, 3.5°""' long, somewhat swelled, 

 ringed with white and brown. The disk yellowish brown ; arms mot- 

 tled, light grayish-brown and dirty white. Arm-spines three or four, 

 the three lowest much more slender, and somewhat shorter, than the 

 upper. 



LIST OF SPECIMENS. 



