254 ZOOPHYTES. 



integuments, modern naturalists have followed Dr Farre in assuming this 

 creature as a type for illustrating the structure of ascidian hydrse. 



The specimen fig. 5, exceeded 18 lines in length, and 2 in diameter, 

 while the animals were quiescent. Owing to their extraordinary multi- 

 tude, no part whatever of the substance invested was visible among them. 

 It was studded by the interspersion of numerous yellow corpuscula. But 

 I could discover none in the body of those hydras manifesting vigorous 

 animation, though one was contained in each cell of many where the 

 tenant had decayed. 



Here it may be remarked, that when certain ascidian hydrte lose 

 their vigour, the organic portion wastes away, leaving behind it a long ob- 

 tuse hollow cone, containing fertile ova. It is in a similar cone of the 

 preceding species, fig. 3, that an ovum appears. In the present species 

 the precise position was obscured. But in the other, there is a remarkable 

 correspondence with the nature of the Alcyonella stagnorum. When cor- 

 puscula or gemmules were discharged from the zoophyte under discussion, 

 I failed in observing how they escaped. But a most accomplished practi- 

 cal naturalist, M. Van Beneden of Louvain, while giving the anatomy of 

 the hydra at large, in his Recherches sur les Bryzoaires, shews the termi- 

 nation of the oviduct under the root of the tentacula. I deeply regret 

 that my very recent acquaintance with only some of this learned Profes- 

 sor's valuable and interesting works, has prevented me from availing my- 

 self suitably of many useful observations, which I can no otherwise repair 

 than by earnestly recommending their perusal to those desirous of real in- 

 formation. 



Though I did not observe how the ovum was discharged, nor whether 

 as such, or as an active corpuscular gemmule, for this might have pre- 

 ceded my inspection, I found it of ovoidal form, truncate behind, and be- 

 girt by cilia. It was also apparently heavy, solid, and consistent. Several 

 escaped during the course of observation from the specimen figs. 4-6, on 

 July 14, the day after it was obtained, fig. 10. Among these one, fig. 9, was 

 much occupied about a slender hair in the watch-glass containing it ; some- 

 times adhering, sometimes searching around, and evidently betraying what 

 any indifferent spectator would have pronounced its animal nature. Num- 



