212 BRITISH DESMlDIFiE. 



22. E. crennlatum (Ehr.). 



Euastrum crenulatum, Ehrenberg, Meteorp. t. 1. f. IG. Kiitzing, Phyco- 

 logia Germanica, p. 135. 



Germany, Ehrenberg. 



I am unacquainted with the characters of this species. 



COSxMARIUxM, Corda. 



34. C. Palangula (Breb.). 



Cosmarium Palangula, Brebisson, in lit. cum icone (1846). 

 Falaise, JBrebisson. 



M. de Brebisson informs me that " Le Cosmarium Palangula me semble se 

 distinguer du Cos. Cucurbita par sa forme plus cylindrique, tronquee et non 

 en Courge, ses scries de points plus fines, transverses et non longitudinales." 

 I am hoAvever unable to distinguish this species from C. Cucurbita, for the 

 puncta are scattered in British specimens of the latter. 



35. C. lagenarium (Corda) ; segments triangular, all the angles 

 broadly rounded. 



Cosmarium lagenarium, Corda, Aim. de Carlsbad 1835, p. 121. t. 2. f. 26. 

 Brebisson, in lit. 



Carlsbad, Corda. 



36. C. Papilio (Menegh.) ; segments smooth, triangular, with rectan- 

 gular apex ; end view linear, with a lobe at the middle of each side. 



Cosmarium Papilio, Meneghini, Consp. Alg. Eugan. p. 18 (1837) ; Synop. 

 Desmid. in Linn(Ba 1840, p. 223. 



Italy, Meneghini. 



37. C. ventricosum (Kiitz.). 



C. ventricosum, Kiitzing, Phycologia Germanica, p. 136 (1845) ; in lit. cum 

 icone. 



I believe this to be a species of Cosmarium in a dividing state. 



XANTHIDIUM, Ehr. 



7. X. Artiscon (Ehr.) ; segments narrowed at the base ; end margin 

 with numerous elongated spines which are divided at the apex. 



Xanthidium, No. 2, Bailey, A^nerican Journal of Science and Arts, v. 41. 



p. 291. t. 1. f. 15 (1841). 

 Xanthidium Artiscon, Ehrenberg, Verbreitung und Einjluss des Mikrosko- 



pischen Lebens in Sud- und Nord-Amerika (1843). 



West Point, New York, Bailey. 



