CORYNB PUSILLA. 



119 



noticed in the next chapter ; I shall, therefore, here 

 confine myself to a few common examples of the Hy- 

 dro ida and Helianthoida. 



The old genera, Tubularia and Sertularia of Lin- 

 nseus, now divided into many genera, furnish us with 

 the best-known examples. 

 We may take as an example 

 of the first of these, a very 

 common little species, found 

 on stones and sea-weeds be- 

 tween tide-marks, especially 

 in clear rock-pools. I allude 

 to the Coryne pusilla of 

 our present arrangement, to 

 which name Dr. Johnston re- 

 duces five supposed species of 

 authors. This little creature 

 certainly varies much in size ' ^'POKT^ ^ 

 and degree of ramification ; 



but the differences are scarcely sufficient to separate per- 

 manent varieties. It offers us an instance of a very 

 reduced skeleton, the tube being a thin, horny mem- 

 brane, wrinkled cross-wise at very close intervals, and 

 continued, in the shape of skin, over the terminal heads 

 of the Polypes. The animal originates in creeping 

 fibres. These throw up erect stems, from which are 

 irregularly given off branches, each crowned with an 

 oblong fleshy head, of a glassy lustre and red colour, 

 armed with numerous short and thick tentacula, standing 

 out like blunt spikes on every side, and but imperfectly 

 retractile. The mouth is terminal. Though we call 



