376 DESMIDE^. 



tion of the vesicles containing the active molecules, which in 

 Closterium Trabecida as in all other Closteria hitherto de- 

 scribed are placed near to each extremity of the frond. 



13. Closterium margaritaceum Eh7\ 



Plate LXXXVIIL Fig. 5. 



Char. Frond ci/Imdrical, narrow, two to eight times as long as 

 broad, someiohat quadrangular, often slightly constricted, 

 striated. Stride denticulated. Cells containing the revolving 

 particles distant from each extremity. 



Ehr. lufus. p. 93. pi. v. fig. 13. ; Jenner, inloc. cit. p. 196. 



Hab. Piltdown Common ; "VYarbleton ; and in the pond 

 between Ramslye and Broadwater Forest : Mr. Jenner. 



A distinct and very interesting little species : it is some 

 eight or ten times smaller than CI. Trabecula. 



14. Closterium Digitus Ehr 

 Plate LXXXVIIL Fig. 4. 



Char. Frond broad, ovate, cylindrical, four or five times 

 as long as broad; transverse lines of division sometinies 

 triplex. Endochrome^a^cmfec/. Bands ^ye or six, often 

 ivaved. 

 Closterium digitus, Abhandl. der Akademie d. Wissensch. 

 zu Berlin, 1831, j). Q'^. Pleurosicyos 3Iyrio(j)o')dus 

 Corda, Almanac de Carlsbad, 1835, p. 182. t. 5. f. 68, 

 69. CI. Digitus 9 Menegh., 1. c. p. 236. 

 Hab. Bogs at Fisher's Castle, Ashdown Forest ; Scrubbs, 

 Colebrook Park, and between Heathfield and Warble- 

 ton : BIr. Jenner. Aberdeen : Br. Dickie. 



This is one of the finest and most distinct of the nume- 

 rous species described by Ehrenberg, whose figures of Clos- 

 teria are most beautiful and accurate, and Avhose descriptions 

 are not less so. The species of this genus being for the most 



