160 SKETCH OF THE INFUSORIA 



Island, N. Y. The tubes are M'liitish, containing long rows of cor- 

 puscles, strung end to end, each of which contains two round globules 

 looking like air-bubbles. No trace of striw. 



2. NauHcma . (PI. HI, fig. 15.) This figure shows the form 



of corpuscles which filled short robust unbranched filaments, which 

 were exceedingly lubricous. Bunches of filaments about half an 

 inch in length, were found in great abundance on Zostera, &c. at 

 Stouington, Conn. 



3. Naunc7na . (PI. Ill, fig. 16.) This figure shows the out- 

 line of dried corpuscles from a specimen obtained at Stouington, 

 Conn., where it is veiy common. Its filaments are branched, and 

 form larger and longer bunches than the preceding, with which it 

 occurs. 



4. Niuinema . (PI. Ill, fig. 17.) This is from specimens 



found in immense quantities in the Hudson Kiver, at "West Point. 

 The masses have not the green color of the two preceding species, 

 but present a rich brown color. The frustules are in all respects like 

 those of Navicula, and I have often seen them move spontaneously 

 in their tubes, some going one way and others another. 



In PI. Ill, fig. 17, fl, is shown the outline of much longer frus- 

 tules, found in tubes similar to those just mentioned.' 



GLOEONEMA. 



Envelope double, carapace siliceous, mantle tubular, tubes 

 simple, often branched, corpuscles curved, resembling Cocconema 

 in a tube. 



Mr. Bcrkcly has recently published (Ann. and Mag. Nat. Ilist. 

 Vol.7, p. 449) some interesting observations, by wliich he appears 

 to have proved that the only species of this genus, the singular 

 G. paradoxnm, consists merely of rows of ova of some aquatic 

 insect. He watched their dcvelopcment into larvae. I have not 

 seen American specimens. 



schizonema. 



Envelope double, carapace siliceous, mantle tubular, tubes united 

 in bundles, split in some places so as to appear branched, corpuscles 

 like those of Navicula. 



No American species has yet been detected by me. 



