ASTEROIDAL ZOOPHYTES. 175 



While quiescent the hydra is retracted into this lower part, which, 

 large and fleshy, serves as a polyparium for many hundred hydras, whereof 

 a specimen may consist. Being somewhat of fleshy substance, these 

 zoophytes are by some denominated carnosc, and by some, asteroidal. 



The vital functions of the carnose portion are not evident ; it seems 

 of later formation than the hydrae, and its bulk is constantly augmenting. 

 The lowest part much resembles the aspect of leather, and appears 

 to be quite indolent. It is the higher part that is covered by hydrse, and 

 the portion of the surface farthest removed from them becomes gradually 

 smoother. 



As the tendrils, or intestinal organs, descend, nutrition is probably 

 thus transmitted, and it is here that the germ and embryo of the young 

 are generated. 



In so far as hitherto ascertained, the asteroidal race is infinitely less 

 diversified than the hydraoid or ascidian zoophytes. There is nothing of 

 that great variety of form and character displayed by them. The struc- 

 ture of the members of the race is neither equally understood, nor in 

 many j)oints are their habits and peculiarities, alike familiar to naturalists, 

 no doubt owing to their being much more unmanageable, as well as to 

 complete ignorance of their food. The difficulty of preserving specimens 

 any considerable time in vigour, also impedes our investigation of their 

 history. Like many other aquatic animal productions, they are compa- 

 ratively torpid and inactive. Some are rooted to the same spot, incapable 

 of detaching themselves. The motion of others, though they are not fixed, 

 is extremely equivocal ; and all observers have shewn themselves much 

 perplexed regarding it. But it is certain that none belonging to Scotland 

 come under the description of floating, or even buoyant zoophytes. 



For all these reasons, I cannot be so diffuse on this as on various other 

 subjects. But there being many who have never beheld living specimens, 

 and who may be much misled by judging of dead ones, the ajipearance of 

 animated and vigorous asteroidal zoophytes will, perhaps, compensate for 

 other deficiences. The few illustrative figures are carefully and correctly 

 executed. 



All the Asteroidal Zoophytes are marine productions. None of them 



