ADDENDA. 159 



As these last pages .ire preparing for the press (March, 1884) I 

 received material collected by the Rev. H. D. Kitehel in a pond 

 in the vicinity of Maitland, and near Sanford, Orange County, 

 Florida. In it I find several specimens of special interest, which 

 demand the following note- : 



Desmiditjm Diagonum, (Aptogonum Diagonum, Delp.) (Add to 

 page 27). 

 Filaments compressed, perforated, twisted, nol vaginatej 

 cells in end view oblong-elliptic. 



Diameter 32 /^.; thickness 11//.: length of cell about half 



the diameter. 



Lake Jessup, five miles from Sanford, Florida. 



This species described by Delponte in his "Desmidiacearum 

 Sabalpinarum," is, in front view, scarcely separable from 1>. 

 aptogonum, but in lateral view it is distinct. The cell- are 

 oblong-elliptic in end view not triangular. The filaments 



are twisted, and being i -e than twice as wide as thick, pre- 



sent an irregular outline, parts showing the broad front, and 

 parts the narrow sides of the filaments. The margins of 

 cells are notched, and the ends excavated as in 1>. aptogonum. 



SPHAEROZOSMA SPIN! LOSUM, Help. 



This species is noticed, page -">1 , with some feelings of doubt. 

 The specimen referred to was more granular than spinous. In 

 the Florida collection are numerous well-developed specimens, 

 which agree with Delpont's diagnosis in being really spinous. 

 They have the form of cell, the measure, and the arrange- 

 ment of the spines, except perhaps that there are more 

 frequently only two, than three spines, on the margin of each 

 semicell. A fine and distinct species. If the granules of the 

 figure (Plate IV, fig. 14) were drawn out into short spines, 

 the typical plant would be well represented. 



Docidium Ehrenbergii, Ralfs. 



Yar. FloRIDENSE, Wolle. 



Differs from D. Trabeculum, Naeg v described, page 48, and 

 from the typical form of D. Ehrenbergii, of Ralfs, Delponte, 





