FRESH- WATER SPONGES IN THE COLLECTION OP THE 

 UNITED STATES NATIONAL MUSEUM.— PART V. A NEW 

 GENUS PROPOSED, WITH HETEROMEYENIA RADIO- 

 SPICUIATA MILLS AS TYPE. 



By Nelson Annandale, 



Superintendent of the Indian Museum, Calcutta. 



The free microscleres (as distinct from those associated with the 

 gemmule) have not been regarded as of much systematic importance 

 by writers on the Spongillidse, but there seems to be no valid reason 

 why they should not be considered in denning the genera of this 

 family. I propose, therefore, to recognize an American species 

 (Heteromeyenia radiospiculata Mills) as the type of a new genus on 

 account of the peculiarities exhibited by these spicules, and in so 

 doing I may state that I am of the opinion that the genus Dosilia 

 Gray should be revived for the same reason, with Spongilla plumosa 

 Carter as its type. 



ASTEROMEYENIA, new genus. 



Type. — Heteromeyenia radiospiculata Mills. 



Spongillidse which have birotulate gemmule spicules of two types 

 and free microscleres in the form of anthasters. 



The anthasters of this genus and of Dosilia are probably not ho- 

 mologous with those of most of the marine sponges in which spicules 

 of the kind occur, but are produced by the secondary fusion of am- 

 phioxous or rotulate microscleres. In Dosilia plumosa monaxon 

 microscleres are sometimes found, while the tips of the branches of 

 asteroid microscleres often approximate to the rotulate form. 



Two species, both confined (so far as we know) to North America, 

 may be assigned to the new genus, namely Heteromeyenia radio- 

 spiculata Mils 1 and H. plumosa Weltner. 2 They may be distin- 

 guished most readily one from the other by the form of the terminal 



i Ann. Mag. Nat. Hist., ser. 6, vol. 1, 1S88, p. 313. 



2 Arch. f. Naturgesch., 1895, vol. 1, p. 127; see also Annandale, Proc. U. S. Nat. Mus., vol. 37, 1909, p. 

 405, fig. 3. 



Proceedings U. S. National Museum, Vol. 40— No. 1839. 

 80796°— Proc.N.M.vol.40— 11 38 593 



