A NEW FKESH-WATER SPONGE FROM SOUTH 

 CAROLINA 1 



By James T. Penney 

 University of South Carolina, ColumMa, 8.C. 



The first specimen of the neAv species of Spongilla described here- 

 in, containing gemmules, was collected from Horseshoe Pond in 

 Lexington County, S.C, on December 3, 1930. Since then numerous 

 specimens have been taken throughout the year for experimental 

 purposes, all from shallow water. All were exposed to light and 

 were green. This Sfongilla grows on stems and leaves of various 

 water plants that inhabit the pond and on dead twigs. It is rela- 

 tively firm in texture and has a wide range in size. The largest 

 specimen measured 12 cm long and 3 cm wide in the thickest part. 



Genus SPONGILLA Lamarck 



SPONGILLA DISCOmES. new species 



GemmvZes. — ^These are dark brown, owing to the color of the 

 chitinous coats. They occur singly throughout the sponge but are 

 not abundant. Their shape is quite different from that of any 

 described gemmule, as they are biconvex disks (figs. 1, 2). There 

 is no foraminal aperture. They range in size from 348)U, to 376ju, 

 in diameter by llO/i to 130/i, at the center of the disk. The granular 

 zone is confined to the peripheral region of the disk (fig. 1, a), 

 and the air cells that make up this zone are large. The inner and 

 outer chitinous coats are well developed and are closely applied to 

 one another on the side of the discuslike gemmule cell mass (fig. 3). 

 Near the edge of the discus, however, the two chitinous coats 

 diverge, the inner coat remaining closely applied to the cell mass 

 (fig. 3, &). The outer coat of one side of the disk meets that of the 

 other side at the rim of the whole disk and forms a ridge (fig. 2, a). 

 The outer surface of the outer chitinous coat is raised into ridges, 

 which anastomose Avith one another to form polygons (fig. 1, &). In 

 section these ridges show as projections from the outer coat (fig. 3,c?). 



^ This paper is a result of work that has been prosecuted with the aid of a grant from 

 the National Research Council. 



No. 2965.— Proceedings U. S. National Museum, Vol. 82, Art. 24 



172293—33 1 



