ERRATA AND ADDENDA. 



Page 

 61, to synonyms of Desmidium Swartzii, add 



Desmidium bispinosumj Corda, Observ. Micros, sur les Animalc. 

 de Carlsbad, p. 20. t. 4. f. 28 (1840). 

 74, for M. morsa read M. americana (Ehr.), and add the following 

 synonym : 

 Euastrum americanum, Ehrenberg, Verbreiiung und Eiiifluss des 

 Mikros. Lebens in Sud- und Nord-Amerika, t. 4. f. 15 (1843). 

 Substitute americana for morsa twice in the description. 

 86, line 5, for S. read /3. 

 99, to synonyms of Cosmarium Botrytis, add 



Euastrum interstitiale, Kiitzing, Phycologia Germanica, p. 136 

 (1845), according to Kiitzing in lit. 

 101, line 2, dele Sussex. 

 127, add. Sporangia of Staurastrum hirsutum have been gathered 



abundantly at West Point, New York, by Professor Bailey. 

 130, under Staurastrum pungens, dele the reference to the American 



Journal of Science and Arts. 

 213, under Staurastrum pygmceum, add, Mr. Jenner informs me that 

 he has seen this species amongst other Desmidieae which I had 

 forwarded from Dolgelley ; and Mr. Thwaites has given me 

 its sporangia, gathered near Devonport by Mr. Dansey. 



The following additions will render more complete the directions for 

 mounting Alga which have been given in the Introduction. 



The rarer species of Desmidieae are frequently scattered amono-st 

 decayed vegetable matter, so that it is difficult to procure good spe- 



b2 



