(iM-om the Canadian Natiiraiisl and Gcoloi;;/st, Se]>t. 1875.) 



y^ 



ON SOME CANADIAN SPECIES OF SPONGILL^. 



I'-V (.KOHfiK M. DAWSfiN. 



The SpongUlala or fmsh-watcr repi-esentatives of tho marino 

 sponocs, thoup-h very widely distributed, are not yet known to 

 be represented by a oreat number of species. It is probabU- 

 that a systematic exploration of the great North American sys- 

 terns of \: kes and rivers might bring many new forms to liuht. 

 \ ith the exception of S. LonUl, Bowerbank, from the source, 

 of the Columbia Kiver, the only Canadian spongilja which ap- 

 pears to have been described, is .S'. Davsom, of the same author 

 a form mhabiting tlie St. Lawrence lliver near Montreal, and 

 other neighbouring waters. 



Having become interested in the examination of a fine specie^ 

 from the Lake of the Woods, obtained in connection with th. 

 work of the British North American Boundary Commission, I 

 have been induced, at the same time, to examine a number of 

 other specimens in the collection of Principal Dawson. Amon- 

 these, and including the Lake of the Woods form, I find four 

 species which I believe to be undescribed. These are here de- 

 fined, and th. jgh I have not the whole of the literature of the 

 subject at han', provisionally named. 



The descriptions, from the poor state of some of the specimen- 

 are necessarily not in all cases complete; but will, I believe -it 

 least serve for the recognition of the species, with the aid of the 

 figures. 



The first spongillas studied-^', fluviatilis and S. lacustris- 

 belong to two distinct types; and it has been found, on eztend- 



