OPHIOTIIRIX ClIENEYI. 



to 



LIST OF SPECIMENS, 



Ophiothrix Cheney i Lvm.vn. 



OpJiiolJirix Cheneifi Lymax. Procectl. Boston Soc. Nat. Hist., YIII. p. 84. 18G1. 

 OphiuUirix hirsuta? Mull. & Tkoscii. Syst. Astoi'Idcn, p. 111. 



Special 3Iarks. — Radial shields closely granulated ; disk beset with 

 thorny stumps. Length of arms about nine times the diameter of disk, 



Desa^iptlon of a Specimen. — Diameter of disk, 21"""-; width of arm 

 without spines, S.G""' ; length of arm, 170""°'. Tooth-papilke very close 

 set ; they form, as usual, a vertical oval, bordered by a projecting mar- 

 gin of about twenty-six papilla?, the centre being filled in with smaller 

 and lower papilla?. Teeth four or five. Mouth-shields nearly as long 

 as broad, heart-shaped, with a pretty acute point inward ; length to 

 breadth, 2.3 : 2.5. Side mouth-shields somewhat variable, more or less 

 closely soldered to the mouth-shields. Under arin-plates partly sepa- 

 rated by transverse furrows, rectangular, broader than long, re-enter- 

 ingly curved outside ; length to breadth (tenth plate), 1 : 1.3. Upper 

 arm-plates much broader than long, oval, well marked, with a distinct 

 longitudinal rib, sometimes a dent in the outer side, surface bearing 

 microscopic granulations ; length to breadth (twelfth plate), 1.1 : 2.8. 

 Disk, above, closely beset with little stumps, thorny on their tops and 

 sides, the longest of them .5°"°' long ; below, interbrachial spaces with 

 scattered stumps, which near the mouth-shields are more pointed and 

 fewer. Radial shields indistinct, from being covered with large, rough 

 grains, about 35 to a square mm. Arm-spines nine ; the third, fourth, 

 and fifth longest, pretty stout, somewhat thickened at the point ; the 

 three under ones very small, as also the upper one, which is not always 

 found ; lengths to that of under arm-plate, .5, 2.9, 3, 3.1, 3.1, 2, 1.5, 1.2, 

 .5 : 1.2. Tentacle-scales oval ; small, ])ut distinct. Color, in alcohol : 

 above, disk rich Prussian blue, speckled with white ; a light spot on 

 each radial shield ; arms indistinctly banded with darker and lighter 

 blue ; along the middle a fine white line, bordered on each side with 



