54 ZOOPHYTES. 



enlargement or head is environed by from four to about twenty-five ten- 

 tacula, arranged in successive stages, — the prominent summit probably con- 

 taining the mouth. They are all, together with the summit, of muricate 

 structure, very extensile and flexible, and endowed with an adhesive pro- 

 perty. Their resemblance of the human fingers is such, that, before being 

 aware of the name bestowed upon it, I had distinguished this subject as the 

 Hydra digitata, an appellative which might be still conveniently adopted. 

 —Plate XVIII. fig. 1. Colony on a shell. 2. Hydra?, enlarged. 3. Por- 

 tion of a colony, enlarged. 



Colonies in their contracted state, when recovered from the sea, re- 

 semble a gelatinous stratum investing the shell. 



Amidst the profusion of hydra, it is for the most part difficult to get 

 a distinct view of individuals ; and this difficulty is aggravated even be- 

 yond what has been said of preceding embarrassments, from occupation of 

 the shell by such an animal as the hermit crab, which pertinaciously re- 

 tains its place. It cannot be dislodged. 



The product itself is liable to mould in still water, in the same man- 

 ner as we have seen of the Flustra hispida. Whence it is probably a 

 provision of Nature to insure frequent renovation, that the shell shall be 

 occupied by so restless an animal as the hermit crab. 



I do not recollect to have ever seen the Hydra squamata on any 

 other substance than an empty shell, or on one occupied by that animal. 



The profusion, conjoined with the peculiar position of this product, 

 precludes the same minute observation regarding the process of reproduc- 

 tion, as in animals single, free, and distinctly exposed. 



Perpetuation.— Several analogies between the mode of its perpetua- 

 tion, are found with the Tubularise and Sertularise. 



Clusters of ova are borne on the hydra themselves, or in immediate 

 approximation by the Tubularia indivisa and the Tubularia ramea, which 

 latter, we have observed, might be almost incorporated with the Sertularicr. 

 As the ovarian contents advance to maturity, the hydra themselves ex- 

 hibit symptoms of approaching decay. 



External ovarian clusters are borne in like manner by the Hydra 

 squamata, in more resemblance of those of the Tubularia ramea, and simi- 



