4 PBOF. E. A. MINCHIN ON THE [May 2, 



authors have been in agreement as to the names to be employed 

 for the genera or as regards the grouping of the species, especially 

 in the more primitive and interesting section of the Oalcarea 

 Homocoela. 



The characters, for instance, by which Breitfuss defines the 

 genus Leucosolenia of Bowerbank(1864) are such as would exclude 

 from it all, or nearly all, the species which I should refer to it, 

 including, as I have shown elsewhere, even Bowerbank's type 

 species of the genus, L, hotryoides ; while Lendenfeld has always 

 consistently declined to make any use at all of the oldest generic 

 name amongst the Ascons. In short, with the exception, perhaps, 

 of the malarial parasites, there is probably no other group in the 

 animal kingdom in which the nomenclature is in so confused a 

 state as in the Homocoela. The species which forms the subject of 

 the present memoir illustrates well the statement just made. 

 It is a veritable comedy of errors that I have to set forth. 



The name Leucosolenia contorta was given by Bowerbank in 

 1866 [1] to certain small sponges from the Channel Islands — 

 Gviernsey, and the Guliot Caves, Sark. It is not very clear, 

 however, what Bowerbank considered the distinctive characters 

 of his species, since his diagnosis would apply to almost any Ascon. 

 He states that "the form of this sponge is so distinctly diiferent 

 from that of L. hotryoides that .... it cannot well be mistaken 

 for that species .... X. contorta always appears to consist of a 

 mass of contorted inosculating fistulfe." Further, that " the 

 external surface of L. contorta is also sparingly furnished with 

 recumbent acerate spiculse, mostly disposed in a longitudinal 

 direction, and I have never observed like spiculse on the surface 

 of L. hotryoides" He was a little doubtful if his sponge were not 

 really identical with Spongia complicata Montagu (1816), but 

 came to the conclusion that Montagu's figure of complicata was 

 " really a very characteristic figure of Spongia hotryoides of Ellis 

 and Solander," and that therefore the name comjMcata was to be 

 rejected. Finally, Bowerbank remarks that contorta and coriacea 

 might be mistaken for each other in the dried condition, but that 

 "the total absence of defensive spiculte on the cloacal cavity of 

 L. coriacea " (meaning apparently the gastral rays of the quadri- 

 radiates) readily distinguishes it. 



If we put Bowerbank's description into more modern terms, it 

 amounts to this — that L. contorta was characterised (1) bj^ form 

 and appearance (contorted inosculating tubes), (2) by the presence 

 of triradiate, quadriradiate, and monaxon spicules. The term 

 " equiangular " applied by him to the triradiate systems need not 

 be taken into account, since he applies the same term to the 

 sagittal spicules of hotryoides. It is not necessary to point out 

 that the characters given by Bowerbank are not sufficient to define 

 a species of Ascon ; and when it is seen that hotryoides always 

 has monaxon spicules, as I have shown elsewhere, and that contorta 

 may frequently lack them ; that the specimen of hotryoides from 

 wliich Bowerbank figured spicules (Brit. Spong. iii. pi. iii. figg. 3, 4) 



