14 



RHIZOSOLENIA ERIENSIS. 



Rhizosolenia Eriensis. H. L. Smth.— Frustules small, com- 

 pressed, somewhat flattened ; not rigidly siliceous, 6-12 times as 

 long as broad ; length -003--006 in. Annuli on the dry frustules 

 conspicuous, apparently interrupted in the middle, and alternate ; 

 obscure in fluid or balsam. Frustules finely striated. Bristles nearly 

 as long as the frustules, and, with the calyptra, excentric, lying 

 nearly in a line with one margin of the frustule when the flat side 

 is in view. 



Chicago (U.S.) water-supply; very abundant at certain seasons, 

 and very rare at others. Originally noted in Lake Erie, at Cleve- 

 land, O. — S. A. Briggs in " the Lens,"" for Jan., 1872. 



NEW AMERICAN POLYSIPHONIA. 



The following species is described as new, by C. H. Peck, in his 

 Report for 1869, just issued. 



Folysiphonia subcontoita. Peck. — Tufts rigid, 2-3 in. high, 

 loosely entangled, dark red ; filaments slender, naked below, alter- 

 nately, and sub-distantly branched above ; branches short, subequal, 

 naked at the base, much branched above, and expanded into a rigid 

 subsquarrose bushy tuft of ramuli, which are subfusiform and more 

 or less curved or contorted ; tubes four, surrounding a small cen- 

 tral one ; articulations of the leading filaments 6-10 times, of the 

 branches 2-4 times their breadth, those of the ramuli shorter than 

 broad ; tetraspores in the swollen part of the ramuli. — Report, p. 51 . 



Rocks near low water mark. Long Island Sound, at Greenport 

 and Orient. July. 



The filaments are about as thick as hogs' bristles, nearly equal 

 in thickness throughout, constituting a leading stem, with its 

 articulations distinct and very long towards the base, and giving 

 out its branches, which are four or five lines long at intervals of 3-4 

 lines. The plant becomes blackish in drying, and does not adhere 

 closely to paper. In size, consistency, and coloration this species 

 resembles P. fastigia ta ; but in ramification, number of tubes, length 

 of articulations, etc., it is far removed from that species. 



Amexican Desmids. — The seven new species of Desmids described 

 by Dr. Wood in the " Proceedings of the Academy of Natural 

 Sciences," at Philadelphia, are named by him, — Euastrum multih- 

 batum. Euastrum ornatum, Arthrodesmus quadridens, Staurastrum 

 minutum, Staurastrum Lewisii, Cosmarium suborbiculare and Pleuro- 

 tcenium breve. Descriptions in Latin, with measurements, will be 

 found in Hedwigia for 1872, No. 1, p. 3. 



