OPHIOSCOLEX STIMPSONII. 23 



Color, in alcohol, yellow brown. 



Hassler Expedition ; Bai'badoes, 100 flithoms. 



Ophioscolex Stimpsonii sp. nov. 

 PI. I. f. 11-15. 



Special Marks. — Upper arm covered by a thin transparent skin, through 

 which appear the upper surfaces of the arm-bones. Each tentacle furnished 

 with a flap of skin standing outside of it. Lower surface and upper disk 

 covered by thick skin. 



Descnption of an Individual. — Diameter of disk, 7""' Width of arm with- 

 out spines, 1.4"™- Length of arm, 31"™'' Mouth-papillne spiniform, blunt, 

 somewhat rough, imbedded in and nearly covered by the skin. There are 

 nine to each mouth-angle, whereof one stands under the teeth. Besides 

 these there may be seen, on each side, the spiniform tentacle-scale of the first 

 pair of mouth-tentacles. Mouth-shields broad, oval, much obscured by the 

 skin ; length to breadth, .6 : 1. Side mouth-shields very small ; not meeting 

 within, nearly buried by the skin. Under arm-plates not visible except on 

 drying or removing the skin, when they appear as small shield-shaped 

 bodies, with an angle within, the sides re-enteringly curved and a strong- 

 notch without. In the same way may be distinguished the side arm-plates, 

 which meet below, but stop above at the level of the upper surftice of the 

 arm {Fig. is). At the tip of the arm the under arm-plate is nearly circular, 

 and is set, like a wedge, between the outer ends of the elongated side arm- 

 plates {Fig. 15). There are no upper arm-plates at all, and the arm-bones are 

 to be seen through the thin skin, both at the base of the arm {Fig. 12) and at 

 its tip {Fig. 1^). Disk covered above and below with a thick but tender skin, 

 there being neither scales nor radial shields visible. Arm-spines, outside the 

 disk, three; short, slender, a little rough; the lowest one longest, namely, 

 .7"™ long. Tentacle-scales are represented by narrow pointed flaps of skin, 

 one standing outside of and close to each tentacle. 



Color, in alcohol, gray brown. 



Dr. William Stimpson ; off Sombrero Key, 240 fathoms. 



It will be seen that this species does not agree with all the characters of 

 Ophioscolex. Its under arm-plates (nearly as in Ophiomyxa) and the flaps to 

 the tentacles are features of diflerence. The type Ophioscolex glacialis, which 

 seems to have a naked thick-skinned disk, is really covered by thin, fine. 



