Wood.] 1'JO June 18 



FAM. DESMIDIEAE.* 

 GEN. PALMOGLOEA. 



p. CLEPSYDRA. Wood. 



P. saxicola et bryophila, in gelatina acliroa interdum dilute viride 

 nidulans ; cellulis cylindricis, cum polis obtuse truncato-rotundatis, diam- 

 etro 2-3 plo longioribus ; lamina clilorophyllacea axili, plerumque indis- 

 tincte, saepe nulla ; plasmate dilute viride ; nucleo plerumque distincto ; 

 zygosporis subfuscis aut subglobosis aut enormiter in clepsydrae forma ; 

 membrana externa enormiter excavata et sulcata. 



P. living on rocks and mosses, swimming in a transparent, sometimes 

 light green jelly ; cells obtusely truncated, rounded at the ends, 2-3 

 times longer than broad ; chlorophyll lamina axillary, mostly indistinct, 

 often wanting ; endochrome light green ; nucleus generally distinct ; 

 zygospore subfuscous, either subglobose or of an irregular form, 

 somewhat resembling that of an hour-glass ; external coat irregularly 

 excavated and sulcate. 



Diam. yMo"- 



Hab. In rupibus et in muscis irroratis ad Chelten Hills, prope Phila- 

 delphia. 



GEN. CLOSTERIUM. 



c. EHRENBERGii. Menegli. 



Hab. Prope Philadelphia. 



C. DIANAE. Ehri. 

 Hab. Prope Philadelphia. 



C. LUNULA. 



Hab. Pi-ope Philadelphia. 



C. ROSTRATUM. Ehrb. V 



Hab. Prope Philadelphia, 



C. SETACEUM. Ehrb. 

 Hab. Prope Philadelphia. 



c. LiNEATUii. Ehrb. 

 Hab. Prope Philadelphia. 



C. LEIBLEINII. KtZ. 



Hab. Pi'ope Philadelphia. 



c. PARVULUM. Naeg. 

 Hab. Prope Philadelphia. 



c. ACEROSUM. (Schrank.) Ehrb. 

 Hab. Prope Philadelphia. 



* I have paid so little attention to the Desmids that I intended at first to omit the family, but 

 afterwards thought best to m.enjtion the few I have identified. 



