Dr. J. E. Gray on the Classification of Sponges, 453 



if the microscopic structure of such a young specimen can be 

 taken to fairly represent the structure of the adult sponge ; 

 and I am more inclined to this opinion as the specimen, which 

 is very like it, but rather more developed, has, even according 

 to Dr. Bowerbank, a different structure, and the same structure 

 as the adult specimen which Dr. Bowerbank refers to another 

 genus. At any rate, it has to be proved that these coral-like 

 sponges do not change their structure from the very early and 

 thin paper-like state till they arrive at their usual thick coral- 

 like condition. Until this is proved, a genus founded on such 

 materials, I am afraid, must be placed in the same category as 

 a genus of sponges from the cocoon of the common leech, and 

 of that founded on the Foraminifera so common on the fronds 

 of Alffte on the south coast of England. At least I think that 

 one must lose confidence m the system proposed m this paper 

 when one finds that a sponge which M. Valenciennes and 

 even Dr. Bowerbank himself formerly considered to be one 

 species, under the name oi Iphiteon 'paniceum^'\% now divided 

 into two genera, viz. Dactylocalyx pumiceus and Iphiteon 

 panicea — that, of two sponges which I had regarded as be- 

 longing to the same species, having the type specimens before 

 me, both, like the former species, coming from the West Indies, 

 one is, according to Dr. Bowerbank, Dactylocalyx pumiceus^ 

 and the other Iphiteon Ingalli. It is natural to conclude that 

 that cannot be a natural division, Avhen it separates into dif- 

 ferent genera specimens which are so nearly allied that natu- 

 ralists who have had considerable experience in sponges have 

 regarded them as the same species, as I am still inclined to 

 regard them, even after Dr. Bowerbank's prolix descriptions 

 and figures, as I think all the differences may be derived from 

 his having taken his fragments from different parts of the 

 sponge ; and the unnatural character of the genus becomes 

 more apparent when we observe that in the genus Iphiteon 

 he places Myliusia and Aphrocallistes — genera which have 

 been adopted by Percival Wright, Oscar Schmidt, and others. 

 In the same manner the genus Dactylocalyx, tliough sepa- 

 rating species that have been regarded as the same, includes 

 in it my Macandreioia — sponges which at any rate have a very 

 different external appearance and general form. 



In the West Indies there are, according to Dr. Bower- 

 bank : — 



1. Dactylocalyx jmmiceus, ip. 77] Iphiteon panicea, p. 324; 

 Ip)hiteon Ingalli, p. 331. 



2. Iphiteon callocyathes \ Myliusia Grayii] Dactylocalyx 

 polydiscus. 



