484 Mr. A. H. Hassall's Description of 



their nature is, that they are organs destined to contain the 

 ova until they have arrived at a certain degree of maturity, in 

 fact, ovaries, and if not ovaries, the ova themselves in a very 

 early stage of their formation. 



I have been induced to raise this species to a generic rank, 

 principally from the arrangement of the ova in circles, -which 

 is, I believe, peculiar to it. Some weeks ago, when at Belfast, 

 Mr. Thompson pointed out this species to my notice, say- 

 ing, at the same time, that he had forwai'ded it long since 

 to Dr. Johnston as new ; its distinctive characters had how- 

 ever been made out by myself long previous to this interview 

 with Mr. Thompson, and reference is made to it in my Cata- 

 logue*. 



This zoophyte, as well as the succeeding species, exhibits in a 

 very remarkable degree that " close adhesion to life," the usual 

 accompaniment of a low organization, which renders this class 

 of animals so patient of injuries which would be fatal to 

 beings of greater complexity of structure. I have on more 

 than one occasion seen the polypidoms of this and the follow- 

 ing species enveloped in a firm coating of ice ; on immersion 

 of either of these in sea-water the coating has become dis- 

 solved, and the polypi have protruded their feelers, and have 

 appeared as active as though they had never been exposed to 

 such a very low degree of temperature as would have de- 

 stroyed the life of more highly organized animals. From this 

 it is apparent that their sensibility cannot be very great. 



Dublin bay, on Fucus serratus ; not uncommon. 



We now come to the description of the second genus. 

 Order ZOOPHYTA ASCIDIOIDA. 

 Family ALCYONiDULyE. 

 Genus Sarcochitum. 

 Character. — Polypidom encrusting-, fleshy, covered with numerous 

 prominences of irregular form and unequal size, from which the po- 

 lypi issue ; ova circular, scattered singly throughout the polypidom ; 

 a dark brown body of a circular form tilled with small round granules 

 is apparent in great numbers through the polypidom. — Polypi asci- 

 dian. 



Sarcochitum poly own. — Polypi with twenty tentacula. 



This species is also usually found investing Fucus serratus^ 

 the frond of which it sometimes covers to the extent of several 

 inches. The crust is thin and fleshy, and covered with nu- 

 merous large eminences of irregular form and unequal size, 

 which exhibit a puckered appearance in the centre, and from 



* Published in the 'Annals' for Nov. 1840, p. 170. 



