52 U.S. NATIONAL MUSEUM BULLETm 2 72 



Sponges encrusting, flat; coloration black to dark gray. Consist- 

 ency extremely hard and firm, ranging to delicate in some species. 



Apparently restricted to tropical regions of Africa and Asia. 



Discussion. — The genus Corvospongilla was one of the first taxo- 

 nomic subdivisions introduced in the formerly recognized subfamily 

 Spongillinae, in which the conglomerate genus Spongilla seemed to 

 have survived to present days apparently without much challenge. 

 The presence of typical birotulates as free microscleres in the sym- 

 plasm of sponges, the gemmoscleres of which are amphioxea or 

 amphistrongyla, certainly fully justified the introduction of the new 

 genus Corvospongilla by Annandale (1911c). However, that author's 

 choice of S. loricata Weltner as its type species must be regretted, 

 since this African species was insufficiently described and a type 

 specimen apparently was not preserved. Thus it happened that 

 Annandale himself considered a number of specimens from India and 

 East Asia as distinct species, a view which has not been challenged 

 by any of the numerous subsequent authors. 



This genus comprises three quite distinct groups of species, differing 

 from each other by a number of decisive criteria. The spicular com- 

 ponents of C. loricata are more or less shared by C. hurmanica and C. 

 lapidosa, and apparentlj'- by C. zamhesiana of which little information 

 was available for this study; the megascleres in this group are stout 

 amphistrongyla, often inflated at their extremities, and usually 

 entirely smooth. The second group is represented by C. bohmii, C. 

 micramphidiscoides, and C. scobrispiculis, in which the megascleres 

 are slightly smaller and entirely covered with rounded tubercles or 

 blunt spines. The third group is somewhat aberrant and can easily 

 be distinguished by the possession of amphioxea as megascleres; it 

 is represented by C. ultima and C. caunteri. 



In the C. loricata group the intrageneric relationship of all species 

 recorded is difficult to review, and future additional collections 

 together with detailed morphometric and ecological comparisons are 

 highly desirable. All show strikingly similar skeletal and other spicular 

 components, and the justification for their specific separation can 

 already be doubted. 



In the C. bohmii group only the nominal species can be readily 

 distinguished from the remaining two by its characteristic micro- 

 birotuiates, whereas C. micramphidiscoides and C. scabrispiculis display 

 close affinities to each other, though their separation is stiU possible. 



The group represented by C. ultima and C. caunteri is most charac- 

 teristic not only by their amphioxous megascleres and more or less 

 delicate skeletal structure, but also by tlie frequent presence of free 

 gemmules, which in C. caunteri possess a pneumatic coat displaying 

 minute but clearly defined air spaces. 



