The reader is requested to compare some of the figures last 
referred to with the descriptions rs a a and D. 
aculeatum, page 289.” 
14. Euastrum ———.. (Fig. 14; Pl. 1.) Binary, corpuscles trian- 
gular, each angle terminating ina sharp spine. Hab. West Point.» » 
I have seen several other species of Euastrum, but the sili 
figured is sufficient to give an idea of the variety and ——- 
the forms in this interesting genus. 
Cuosterwm. (See Figs. 30 to 38, Pl. 1.) vis 
Ehrenberg makes of this genus a distinct family of Infusoria, 
which he calls the Oléstetina, and characterizes thus: 
“ Polygastric (distinctly or probably) without alimentary ca- 
nal, without appendices, polypidoms having the form of a wand, 
(“ baguette,” ) thread or spindle, by spontaneous division, oe 
Sived and movable in the opening of the carapace.” 
LT have before stated that I consider the genus Closterium most 
closely related to Etiastrum, and therefore with the Desmidiacea 
generally. This relation to Euastrum is manifest in their apparent 
identity i in internal structure, the chief diffe fference between them 
is only in the erternal forms, and even in them, we find there is 
aperfect transition from the highly lobed and tabular forms of 
some species of Euastrum, to the entire, elongated and fusiform 
species of Closterium. It is therefore without hesitation that I 
place Closterium (as indeed most writers do) among the Desmi- 
ea, 
These has been much discussion of the question, Ncdeekiver the 
Closteria are plants or animals, and as this inquiry is one.of gen- 
eral interest, the decision of which will affect the position of all 
the family Bacillaria, I maybe excused for giving at some 
length, an account of the present state of the question. Eh- 
renberg gives the nore reasons for believing the Closte- 
Mla to be animals. 1. Their voluntary motion. 2. Their termi 
hal'openings. 3. mai incessantly moving organs placed against 
the ¢ ie and sometimes projecting. ‘A, Their BpOntaiCoNs 
divi 
‘Movred in in his celebrated memoir “ Sur les Closteriées,” (some 
hotice of which’ may be found in this Journal, Vol. xxv, p. 122 > 
Supports the view rai the ea a see. 
Vol. x11, No. 2.—July-Sept. 
