FOOD, AND MODE OF CATCHING IT. 95 



ascertain how the latter were captured, I threw one 

 of them into a jar in which was a Cydippe which had 

 evidently not dined that day. It was instantly caught 

 by one of the tentacles. The Acaleph at once became 

 very animated, and performed a series of somersaults 

 until it had succeeded in hitching the tentacle which 

 held its prey across the widely-gaping mouth as over 

 a pulley. The tentacle was then contracted by suc- 

 cessive jerks until the morsel was hauled up and 

 dropped into the stomach. This experiment was fre- 

 quently repeated, with precisely the same results, by 

 myself and friends with the same and other specimens 

 of Cydippe." 



The Beroes, notwithstanding the excessive delicacy 

 and translucency of their structure, have voracious 

 appetites, and will eagerly devour minute Crustacea 

 measuring from a line to a line and a half in length ; 

 the bright colouring of the prey so swallowed con- 

 trasting most conspicuously with the crystalline trans- 

 parency of the body in which they are enclosed. 



If, however, the Beroes thus live upon the small 

 Crustacea, they in turn furnish a supply of food to 

 Medusae more powerful than themselves. "On the 

 12th of May," writes Mr. Patterson, "I took a small 

 Medusa of the genus Callirhoe, and placed in the glass 

 vessel with it a Beroe which had been taken at the 

 same time. While the latter was swimming round 

 the glass with that lively and graceful movement for 

 which it is so remarkable, it came in contact with 

 the filiform tentacula attached to the arms of its 

 companion. The arms instantly closed, and the Beroe 

 was a prisoner. I endeavoured to separate them, and 



