74 Rev. T. Hincks on Clavatella, a new Genus 



polypoid buds, which pullulate from two opposite points on 



the lower portion of the body. 



In the remarkable extensibility of the body, and the position 

 of the reproductive buds on the lower portion of it, Clavatella 

 resembles Myriothela. The character of its sexual organs is so 

 far unique. I have failed to detect any horny investment, either 

 on the creeping thread which unites the polypes, or round the 

 base of the body itself. The examination of these portions of 

 the structure was attended with extreme difficulty, as the zoo- 

 phyte almost always occurred amongst a forest of minute Algae. 

 But in the only case in which I succeeded in detaching an indi- 

 vidual with a portion of the thread, I was unable to find any 

 hard covering. The thread seemed to be cased in a delicate 

 membranous skin. 



The species may be characterized as follows : — 



C. prolifera, Hincks, n. sp. (PI. VII. figs. 1, 2.) 



Polypes slender ; head and centre of the body opake white ; 

 tentacles (in the mature zoophyte) six or seven, surmounted 

 by large globular tips, — a patch of opake white just below the 

 tip, and another towards the base of each ; reproductive zooids 

 hemispherical, yellowish white, with six bifurcate tentacles 

 round the body, — the longer branch capitate, and resembling 

 the arm of the alimentary polype, the other supporting a suc- 

 torial disk, and forming a locomotive and prehensile organ ; 

 six red specks at the base of the tentacles, on the proximal* 

 aspect of the body. 



The polypes of Clavatella prolifera possess a remarkable power 

 of altering the dimensions of the body. At times it is greatly 

 elongated and attenuated, and they then present the appearance 

 of very delicate threads. If disturbed, they suddenly contract, 

 and in this state often assume a somewhat flask-like form (PI. VII. 

 fig.2«). 



The somatic cavity, pervading the centre of the body, is en- 

 closed by an opake- white endoderm. The external portion (ecto- 

 derm) which surrounds it is transparent. 



On one occasion I found an Annelid of very considerable size 

 in the stomach of a polype, which had evidently gorged itself, 

 and was much distended and altered in shape. 



The tentacles, as well as the body, ai'e extensile ; the number 

 is variable, and probably dependent on the age of the polype. 



* Throughout this paper I shall employ the terms "proximal" and 

 "distal," as defined by Prof. Huxley ('Oceanic Hydrozoa,' pp. 4, 5); the 

 latter to designate the "growing," and the former the "comparatively 

 fixed " extremity of the hydrosoma. 



