Spongillidae. 247 



We have, thoroforo, to deal with 10 genera and subgenera in con- 

 sidering the Spongillid fauna of the Continent. 



Of these, two subgenera (Eiispongilla and FAinaplus) niay be regar- 

 ded as cosmopolitan. 



Euspongilla is at once the most primitive in the family and perhaps 

 the most generally distributed. In Afriea it is represented by only two 

 species, so far as we know at present, and both ot" these occur in Lower 

 Egypt. One (SponglUa alba) is a widely distributed and abundant Indian 

 form, doubtfidly distinct as a species from tlie cosmopoHtan »S. lacustris ; 

 while the other (S. biseriata), which is closelj related to the N. American 

 and Indian species Ä. craterifortnis (Potts), has been found both in the 

 deka of the Nile and in the Zambesi river-system. It would thiis seem 

 that the subgenus is very poorly represented in Afriea; but it must be 

 noted that many of the species are usually found in ponds and other small 

 masses of water and that such situations have been very little examined 

 in Afriea so far as sponges are concerned, and, iudeed, are scarce in most 

 parts of the Continent. 



Eunapius is represented in many countries only by what are practi- 

 cally races and varieties of a single cosmopoHtan species, Spongilla fragi- 

 lis, Leidy. In Afriea, hoAvewer no less than four distinct species have 

 already been found, one of which (S. nitens) is e-vidently of wide distri- 

 bution in the eastern tropical part of the Continent, the remainder being 

 only known for the most part from singh^ records. In India also four 

 species are known. 



The genus Ephydatia is very widely distributed, but chiefly in tempe- 

 rate climates, reaching its acme in Japan. In Afriea the only fonn as yet 

 discovered is a local race of the cosmopoHtan E. tiuviatilis and has only 

 been found south of the Limpopo. 



Dosilia, on the other band, is essentially tropical and subtropical in 

 its ränge, consisting of three closely allied species which are regarded by 

 some authors as varieties. One (D. plumosa) is found in the Indian Pen- 

 insular Area, one (D. palmeri) in Mexico and the neighboiu-ing states, and 

 one (D. brounii) in the AVhite Nile. 



Tubella appears to have its headquarters in North and South America, 

 but is represented by scattered species in Europe, tropical Asia and Au- 

 stralia, as weU as by one (T. pottsii) in the Congo System. 



None of the foregoing genera and subgenera can be said, in the 

 present State of our knowledge, to cast much light either on the distri- 

 bution of the African fauna within the Continent or on its relations to the 



17 Michaelsen, Deutsch-Südwestafrika, 



