GRAY BRITTLE-STAR. 31 



peculiar habit, as well as by minute but more easily- 

 definable characters. The rays of the Sand-stars have a 

 whip-like or lizard-tail appearance ; those of the Brittle- 

 stars look like so many Centipedes or Annelides, attached 

 at regular distances round a little Sea-urchin. The latter 

 are much more flexible than the former, more irritable, 

 more brittle, nevertheless much more tenacious of life. 

 When dried, the ray-spines of the Brittle-stars stand out 

 from the ray ; whereas in the preserved Sand-star they are 

 appressed to its sides. The cirrhi, too, which are seen 

 between each row of spines in the living animal, are pin- 

 nate, or as if covered with short tubes in the Ophiocomse. 

 The Brittle-stars are much more active animals than the 

 Ophiurae ; they seldom remain quiet for a moment, but 

 are continually twisting about their arms, and if laid hold 

 of they break up into little pieces with wonderful facility, 

 each fragment of an arm also breaking itself up into 

 smaller pieces ; and, frequently when we seize one of these 

 creatures, in a moment we find nothing but the disk re- 

 maining. They can reproduce their arms in the same 

 manner as the Asteriada. 



This habit of breaking themselves into pieces when cap- 

 tured, renders it very difficult to preserve them for col- 

 lections. Dr. Johnston has given the following directions 

 for their preservation in the ninth volume of the Magazine 

 of Natural History : — " The Ophiurse must be brought from 

 the shore in sea- water, where, after being allowed to remain 

 at rest for an hour or so, they will crawl about and expand 

 themselves on the bottom and sides of the vessel. When 

 in this state remove them with the fingers cautiously, and 

 plunge them instantly into a large basin of cold fresh 

 water. They die in a state of the most rigid expansion, 

 and so quickly that even the most brittle species have no 



