291 
present discovery extends its range more than a thousand miles. 
My specimens agree with his description, except that the undula- 
tions are less numerous and the cells rather shorter. Diam.=20 p; 
length=110 ». Fig. 1. 
* P. Cylindrus (Ehrb.) Breb. var. Silesiacum Kirch. (532). Wake 
Forest, N.C. Scarce. Agrees well with the description. Diam. 
=14 #; length=42 p. Fig. 2. 
Closterium maculatum Hast. Bridgeport,Conn. Rare. Nearly 
twice as large as Hastings’ measurements, but otherwise agreeing 
with his description. Striae of minute granules and interrupted 
irregularly. Diam.=50 yp. Prof. Nordstedt suggests that this 
Species may possibly be a form of CZ. arcolatum Wood. Fig. 7. 
Cl. angustatum Kiitz., var. clavatum Hast. Bridgeport, Conn. 
Scarce. Diam.=25 ». This seems well marked, but only a few 
Specimens were found. Fig. 6. 
* Cl. abruptum West. (395). Holderness, N. H. Frequent. ° 
Variable in length. Occasionally a specimen is longer than 
West’s measurements. Diam=12 »; length=84-200 p. Fig. 5. 
* Cl. Cynthia De Not. (537). Wake Forest, N. C. Frequent 
and typical. Striae very fine and numerous. Diam =12-14 p; 
length=100-120 p. Fig. 3. 
Cl. tumidum nov. nom. (416). (C2. Cornu 3 of Ralfs.t; Cl. 
cornu of Wille’, but not of Ehrenberg®). Burlington, Kansas. Fre- 
quent. Diam. usually 12 »; length= 116-120 p#. Occasionally a 
specimen reaches a diameter of 18-20 yp, representing Wille’s 
forma major®, West found the latter in Maine. Fig. 4. 
Gonatozygon aculeatum Hast. Meredith, N. H. Occasional. 
Seems to be a well-marked species. Diam.=16 yp; length 300 p. 
Aculeae 6-8y long. Fig. 9. 
G. asperum (Breb.) Cleve. (460). Tallahassee, Fla. Rare. West 
reports it from Maine. The single specimen found was about 
twice as long as the type, but otherwise the same. Diam.—6 p; 
length=260 p». Fig. 8. 
4 Ralfs, J. British Desmids. 176° p/. 30. f 64 and é, 1848. : : 
5 Wille,N. Ferskvandsalger fra Novaja Semlya. Ofversigt af Kongl. Veten- 
skaps. Akademiens Forhandlingar, 1879, //. 24. f, 80,87. 1879. 
6 Ehrenberg, C. G. Die Infusionsthierchen als volkommene Organismen. 94. 
B16. f. 5. 1838. 
