1887.] NATURAL SCIENCES OF PHILADELPHIA. 265 



Carter lus. The gem mules were young, to be sure, but the tendrils 

 were there and the novelty of the species was easily seen. 



Further down the stream, where the public road crosses it by an old- 

 fjishioned "covered-bridge," in the shelter of it and, incidentally, pro- 

 tected from the trampling of cattle by fences of barbed wire, was found 

 the very headquarters, the "zoological garden" of this species. Nearly 

 every stone and the gravelly bed of the stream between them, was 

 covered with it just under the surface of the water. The masses were 

 not large, say five or six inches in diameter; and while thickest near 

 the middle, tapered off into a delicate nimbus around the edges. This 

 appearance was more conspicuous during the early autumn, when, the 

 thicker portions having become brown with age, a new growth, 

 probably from the germination of some of the older gemraules, had 

 started around the edges, and in this no gemmules could yet be 

 found. Soon after, the bunches began to dwindle in size, and on 

 the day after Christmas of that year, I find it recorded, "the masses 

 have all been washed away, leaving a slight muddy incrustation, 

 consisting partially of filiform algae, with numerous sponge gem- 

 mules and their tendrils, which have aided in binding the particles 

 of a deposit of silt or fine mud into a persistent film, that will prob- 

 ably last until the time for germination next spring." The follow- 

 ing year the amount of this sponge, in that locality, was much re- 

 duced, and since that date I have had no opportunity to examine 

 it. 



In common with the other two species, this fresh-water sponge is 

 very loosely held together ; with the same conspicuous wave-lines of 

 spicules marking its surface. On the gemmules, the broad ribbon- 

 like tendrils, seemingly pierced by the tapering ends of the forami- 

 nal tubules, are in strong contrast with the slender, thread-like fila- 

 ments of C. tenosperma, next to be described ; still less do they re- 

 semble those inconsequent, almost embryonic, features of C. tubisper- 

 ma and C. {Dosilia) stepanowii. Yet the spicules of this species, 

 skeleton, dermal and birotulate, closely resemble those of G. tuhis- 

 perma and both are suggestive of II. repens. 

 (4) Carterius tenosperma, Potts. (PI. VI, fig. vi; PI. XII. fig. iv.) 



Spongilla teidaspernia, Potts. Proc. Acad. Nat: Sci. Phila. July 

 1880. 

 Spongilla tenosperma, Potts. Proc. Acad. Nat. Sci. Phila. Nov. 



1880, p. 357. 



Carterella tenosperma, Potts. Proc. Acad. Nat. Sci. Phila. June 



1881, p. 150. 



18 



