31 INTRODUCTION TO ZOOLOGY. 



change of place, can perform with rapidity and case a rotation 

 which would put to shame the most finished pirouettes of the 

 opera-dancer. During these movements the form of the body 

 is not unfrequently altered, and the lobes of the mouth become 

 more or less distended. These diversified aspects are further 

 increased by the distension or the retraction of two tentacula, 

 furnished on one side with cirri, which are sometimes spread 

 out like delicate hairs, and, at others, are spirally convoluted. 

 By these singular organs the little Beroe can attach itself to 

 the sides or bottom of its glassy prison, and ride, as if at 

 anchor, moored by these singular and delicate cables. 



Its food appears to consist of small Crustacea,* which may 

 be seen in the transparent stomach for some time after being 

 swallowed. Insensibility to pain, and a continuance of vitality 

 for a long period in mutilated parts, seem to prevail in this, as 

 in some of the other animals already mentioned. When, after 

 a storm, Bcroes are taken in a shattered condition, each 

 fragment of their body continues the action of its cilia unim- 

 paired. On one occasion, the author severed one of these 

 fragments into portions so minute, that one piece of skin had 

 but two cilia remaining attached to it; yet the vibration of 

 these organs continued for nearly a couple of days afterwards. 

 On another occasion, a species of Medusa or small jelly-fish, 

 which was furnished with four arms, came in contact with a 

 Cydippe confined in the same glass; the arms immediately 

 closed, and the Cydippe was a prisoner. The diameter of the 

 Medusa was not much greater than that of a sixpence ; but 

 it maintained its hold, though we endeavoured to liberate the 

 captive by pushing its conqueror with the stick of a camel-hair 

 pencil. When, at length, it had regained its liberty, the 

 Medusa was found to have cut away a piece fully equal to the 

 one-third of that side it had seized, or a sixth of the entire 

 bulk of the body; yet the Beroe seemed quite unconscious of 

 this mutilation, and did not evince any diminution of its 

 activity or its enjoyment. 



It is one of the advantages of natural history pin-suits, that 

 they furnish occupation and enjoyment when, from recent 

 indisposition or other causes, either mind or body is unfit for 



* We saw thorn, in May, 1835, .feeding on two species then undescribcd, 

 but now named and figured by Teraploton in the Trans, of the Entomo- 

 logical Society, vol. ii. 



