OBITUARY OF SCIENTIFIC MEN. 363 



at its distal end. In Gh-antia both systems, the incurrent and excurrent intersti* 

 tial canals, become very nearly obsolete, but large intermarginal cavities or cells 

 imbibing the water through their pores on the distal extremities, and becoming 

 enlarged and elongated until they reach the parieles of the great central cloaca, 

 into which they discharge their contents, each through a single osculum, into a 

 short depression or cavity in the parietes of the great cloaca, and this sliallow 

 cavity .represents the nearly obsolete system of excurrent canals." 



The reproduction of sponges is as yet imperfectly understood, but 

 as the ova and spermatozoa seem to have been distinctly observed in 

 Tethea and ovarian vessels filled with ova are known in Spongilla, a 

 regular reproduction by fertilized ova may be assumed to occur where 

 it has not yet fallen under notice, and there is no doubt of gemmation 

 also occurring ; besides which, the colonies of animalcules which ac- 

 cording to our idea constitute the sponge, occasionally divide, each. 

 portion separately increasing in numbers so as to form a complete new 

 compound bodj^. Many particulars respecting the known ovaria of 

 sponges, and their germination internal and external are given by Dr. 

 Bowerbank. A very important part of his work is also devoted to 

 the explanation of his mode of classification, incomparably the best 

 that has yet been proposed, and the discussion of the circumstances 

 which afford the best characters for genera and species. The whole 

 is illustrated by an admirable series of plates by Aldous, forming a 

 most interesting specimen of what can be accomplished in the repre- 

 sentation of microscopic objects. Of the value of the work as a con- 

 tribution to natural science we feel that we cannot speak too highly. 

 It adds to the important obligations conferred on science by the Ray 

 Society, a happily planned association deserving extensive support, to 

 which Canada ought to contribute more members than it has yet 

 done. W. H. 



OBITUARY OF SCIENTIFIC MEN. 



Death has been busy in the world of science since our last issue ; and we 

 must not omit to record our losses, though our readers may, most of them, 

 have seen elsewhere fuller notices of the eminent men whom we can do little 

 more than name with the respect due to their talents and worth. 



Mr. Hush Cuming, whose reputation is world-wide as a Natural History 

 traveller and collector, and as a conchologist, possessing the finest series of 

 shells ever brought together, died at his residence, Gower Street, London, on 

 the 10th of August. He has contributed largely to the advancement of the 



