1904.] SPONGES OF THE GENUS LEUCOSOLEXIA. 



38/ 



Ascandra hotryoides Fristedt, 1885, K. Yetensk.-Akad. Hand- 

 lingar, xxi. no. 6, p. 9. 



Ascaltis hotryoides Hanitsch, 1890, Trans. Liverpool Biol. Soc. 

 iv. p. 223. 



Leucosolenia hotryoides Minchin, 1896, Ann. Mag. ISTat. Hist. 

 (6) xviii. p. 359. 



Leucosolenia Sofo'yoiV^es Breitfuss, 1898, Arch. f. Naturges. Ixiii. 

 i. p. 210. 



Ascandra hotrys Breitfuss, 1898, 1. c. p. 213. 



Leucosolenia hotryoides Rousseau, 1903, Mem. Soc. Malac. 

 Belgique, xxxvii. p. 5, fig. 1. 



Leucosolenia hotryoides Allen, 1904, J. Mar. Biol. Assoc, n. s. 

 vii. p. 185. 



(a) External Characters. 



This sponge is only known to occur in one kind of situation and 

 under one form. It is always found growing over algae, forming 

 a basal reticulum of finer tubes attaching it to its support, from 

 which arises a dense cluster of short smooth oscular tubes. This 

 extremely characteristic form is well seen in the figures of Ellis 

 and Solander [7], Bowerbank [1, vol. i. fig. 348], and even 

 Haeckel [3, pi. ix. fig. 10], and enables this species to be distin- 

 guished at once. The form of the sponge is usually compared to 

 that of a bunch of grapes, hence the specific name hotryoides ; bvit 

 since the oscular tubes are at least five or six times as long as 

 they are broad, a. bunch of bananas would be a better comparison 

 as regards form. 



I have not found hotryoides at Roscoif, but at Plymouth it is 

 not uncommon. In Wembury Bay I found it extremely abun- 

 dant, competing with Grantia compressa for the occupation of the 

 algfe on the overhanging sides of rocks, in situations where the 

 sponges ai-e left suspended high and dry at low tide. Its mode 

 of growth may be compared with the bushy form of variabilis 

 growing in similar situations. In fact, the only difference between 

 the two sponges under these circumstances is tha.t in hotryoides 

 the oscular tubes are shorter in proportion to their length and 

 more thickly clustered together, so that the distinctiveness of the 

 external form of hotryoides is more apparent than real as regards 

 mode of growth. The oscular rim in this species is short or 

 of moderate length, and the oscular tube narrows more or less 

 rapidly towards the opening, but in both these respects also the 

 difference from variahilis is rather one of degree. The wall of the 

 oscular tube is greatly thickened by quantities of stout spicules, 

 and the sponge is much tougher and stronger than either of the 

 preceding species. 



(b) Characters of the Sjnculation. 



Since the spiculation of this species is modelled, so to speak, 



25* 



