CHARACTERISTIC DEEP-SEA TYPES. — OPHIURANS. 109 
North of Cape Hatteras the species of starfish procured by the 
* Blake” are identical with those described by Professor V errill 
from the dredgings of the United States Fish Commission. 
I would only mention here, as the most interesting of the 
species we found, ten-armed specimens of Brisinga coronata. 
(Fig. 387.) This species forms the subject of an elaborate 
paper by the younger Sars, and I have here reproduced one of 
his figures. 
OPHIURANS.' 
Among Echinoderms there are two families, the brittle-stars, 
or Ophiuride, and the branching-stars, or Astrophytidze, which 
are distinguished by a peculiar axis in the arms, made up of 
articulated bones somewhat like vertebre. The disk or body is 
Fig. 389. — Ophiocreas spinulosus. 4j. 
usually distinctly set off from the arms. These last contain no 
prolongation of the central digestive cavity, as they do in the 
starfishes proper. 
1 Mr. Lyman has prepared the account of the ophiurans. 
