324 Miscellaneous. 



composed of contractile fibres. There are four pairs of spermatic 

 reservoirs*, each consisting of a double vesicle, the outer one much 

 larger than the inner, and both furnished with a duct ; these ducts 

 Unite, to open externally at the intersections of the third, fourth, 

 fifth, sixth, and seventh segments, by orifices which are rendered 

 visible by pale latero-cenlral spots. The two vesicles and their ducts 

 are situated behind each of the dissepiments. These reservoirs con- 

 tain granular cells, with spermatozoids and Psorospermiae of 0*010 by 

 0*006 millim. ; the latter abound especially in the largest vesicles 

 of each pair. 



In short, P. diffringens, in all the essential parts of its organiza- 

 tion, resembles the species which have already been studied, and 

 confirms the views expressed by me in previous memoirs. — Comptes 

 Bendus, August 7, 1871, pp. 385-387. 



On the Animal of the Glass-rope. By Dr. J. E. Gray, P.R.S. &c. 



Mr. F. Kitton, in Hardwicke's ' Science Gossip ' for March 1872, 

 makes some "Eemarks on Pcdythoa investing the Glass-rope Sponge," 

 and figures some of the animals growing on the surface of a ray's 

 ova-case, evidently considering that this jjroves their parasitic 

 nature. He mentions a second case, in which they were growing 

 on a riband frond of some species of Alga3. 



I regard both these instances as proving just the contrary. 

 " The Algffi had become entangled with the glass-rope." The egg- 

 case of the ray is very often to be found attached by its elongated 

 ends to the glass-rope. I believe the figure only represents some of 

 the eggs or buds of the polypes growing on its surface, to which they 

 have become accidentally attached ; and that they will never come 

 to perfection so as to form a ci'ust or develope the rope-like spi- 

 cules. My reason for believing this to be the case is that the po- 

 lypes are isolated ; they are of very diff'erent sizes, some being very 

 small and others being large ; some are crowded one upon the other, 

 so as to deform their shape, very unlike the uniform crust they form 

 on the glass-rope ; and I bave no doubt of their being incapable, 

 from their position, of developing the usual rope. 



Mr. Kitton states " that the examination of the Polythoa when 

 found apart from the sponge has enabled him to ascertain the spi- 

 cules peculiar to it. Figs. 24 & 25 of his previous paper appear to 

 be the only forms of spicula really belonging to the Polythoa." He 

 omits to state that these spicules are siliceous, like the other spicules 

 found in the rope and bark of Hyalonema, which have not hitherto 

 been found in Palythoa ; and the two forms he mentions from a 

 polype only difi^er from those found in other parts of that coral in 

 being thicker and more spinose. 



* I think it necessary to indicate that the improper name of capsnli- 

 genous (/lands must no longer be employed, or at least referred to 

 D'Udekem, who has formally reverted to the opinion of Leuckart in his 

 well-known work on the genital organs of yEolosoma and Chcetogaster. 



