162 Mr. H. J. Carter on Parasites of the Sponyida. 



Bay on the north coast of Africa (' Annals/ 1872, vol. x. 

 p. 50). 



Of Stephanoscyphus mirahilis Dr. Allman states that it 

 " may be found attached to stones in small patches of one of 

 the horny sponges," of which the figure in the Trans. Linn. 

 Soc. [l. c), being of the " natural size," is about two inches 

 in diameter and half an inch thick in the middle. This con- 

 sisted of a " congeries of tubes which penetrate the sponge- 

 tissue and open on its surface," being, with their contents, 

 " united by a common tubular plexus towards the base of the 

 sponge" ('Nature,' I.e.). 



On the other hand, Spongicola Jistularis is stated by Dr. 

 Schulze to consist of a series of branched tubes (/. c. Taf. xlvii. 

 fig. 8), opening on the surface of the sponge by one end (Taf. 

 Ixv. fig. 1), and closed or blind at the other. Hence 8te- 

 phanoscyphus mirahilis not only differed from Spongicola Jistu- 

 laris in this way, but the former being in a " horny sponge " 

 seems to intimate, although the kind is not mentioned, that it 

 was in a totally different order from all those bearing the 

 hydrozoon so elaborately described and beautifully illustrated 

 by Dr. Schulze. 



In my own case, where the polyps were situated in the 

 interior of the sponge, I liave nothing to add beyond what has 

 already been stated, ' Annals,' I. c. (for the specimen was 

 returned, with all the rest of the sponges dredged up on board 

 H.M.S. ' Porcupine,' to Sir Wyville Thomson last year, 

 'Annals,' vol. xix. p. 432), viz. that "the minute delicate 

 polyps were seated in dilated cavities, apparently of the 

 excretory canals, the disk or head of each polyp averaging 

 1-lOOtli inch in diameter, and supported on a short neck, 

 which ended in a little saccular prolongation that was sunk 

 into the parenchyma or sarcode of the sponge, and charged in 

 its walls, as well as in its tentacles, with thread-cells, &c." 

 But that my object then was chiefly to show that the thread- 

 cells observed by Eimer in Beniera fihulata and Desmacella 

 vagabunda, Sdt., probably did not belong to the sponge, as 

 subsequently confirmed by Schulze's observations (?.c. p. 799), 

 I should probably have paid more attention to the structure 

 of the polyp itself, which, however, from its minuteness, posi- 

 tion, and exserted tentacles, might be inferred to have been 

 a Hydi'oid rather than an Actinozoid polyp like that of Paly- 

 thoa. 



Algoid Parasites. 



Seaweeds. 

 It is not an uncommon occurrence in some parts of the 



