178 ZOOPHYTES. 



the centre, which communicates immediately with the cavity of the 

 stomach. From the base of this organ several delicate tendrils or vessels, 

 whose precise character is not explained, descend into the substance of 

 the specimen. 



The hydrse in full vigour stretch nine lines from the surface of the 

 mass, with which their bodies are incorporated as an integral part. Thence 

 their size exceeds that of any of the hydraoid or ascidian inhabitants of 

 the other zoophytes of Scotland. Each side of the tentaculum is border- 

 ed by cylindrical fleshy prongs, shortening towards its extremity, whence 

 the pectinate aspect. Thus, when completely expanded, a specimen cover- 

 ed by a profusion of such pinnate organs, is a beautiful and ornamental 

 object. — Plate XLII. fig. 1. 



But this display is so rarely to be obtained from larger, that the 

 naturalist must be content with its exhibition from smaller specimens. 

 The hydree contract without any obvious cause ; they sink amidst the 

 fleshy portions, and often remain long in retreat, therefore the subject is 

 unmanageable : they shun the light ; but the recent element, a genial atmo- 

 sphere, and the approach of night, seem to influence their evolution. 



When recovered from the sea, the Lobularia is always in a contract- 

 ed state ; probably it becomes so during its passage upwards, if expanded 

 when below. A smaller single specimen contracted, somewhat resembles 

 a fungus of the Phallus kind, consisting of a head rather enlarged, with the 

 rest downwards of inferior diameter. It is only those of more parts, and 

 greater dimensions, that can be compared to other objects. 



In contraction a specimen is hard to the touch. One of ample size, 

 completely distended with the hydrae displayed, requires a cubical vessel 

 of seven inches to contain it ; that is, the side of the cube must be seven 

 inches. 



The Lobularia can evacuate itself at will, whether in or out of its 

 element, but the means of effecting either this, or of attaining intumescence, 

 is obscure. Evacuation is a speedy process; repletion occupies many 

 hours. Therefore the absorption is much slower than the discharge. 



But all its sensible changes and motions are very slow. Nothing 

 more is to be observed of the prolongations or fingers than their inclining 



