9G BRITISH DESMIDIEJB. 



7. C. granatum (Breb.) ; constriction of frond forming a linear notch 

 on each side ; segments compressed, smooth, truncato-triangular. 



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



Dolgelley and Penzance, very rare, /. R. Bristol, Mr. Thwaites. 



Falaise, Brebisson. 



Frond rather larger than those of Cosmarium bioculatum and C. Meneghinii, 

 twice as long as broad, deeply constricted at the middle, the constriction 

 forming a linear notch on each side ; the segments are quite smooth and 

 entire and slope off rapidly from near the base, so that they would be trian- 

 gular if the end were not truncate. 



Not only were the few fronds that I have seen of this species of a larger 

 size than a figure sent me by M. De Breljisson would indicate, but their 

 segments tapered more rapidly. I have seen neither the transverse nor the 

 end view. 



This plant may be identical with Cosmarium Papilio, Meneghini. 



Length of frond ^^^3^ of an inch ; breadth of segment at the base -j-gV2 > 

 breadth of segment at the end ^ttq ' breadth of frond at constriction ^xtt* 



Tab. XXXII. fig. 6. a. mature frond; b. empty frond. 



ft Margin of segments crenate ; surface not granulate. 



8. C. Meneghinii (Breb.) ; frond smooth, deeply constricted at the 

 middle ; segments subquadrate, sides and end bicrenate. 



Cosmarium bioculatum, Menegh. Consp. Alg. Evg. p. 18 (1837) ; Synop. 



Desmid. in Linncea 1840, p. 220 {not Heterocarpella bioculata, Breb.). 

 Euastrum bioculatum, Kiitzing, Phycologia Germ. p. 136 (1845). 

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



Ambleside, Westmoreland, Mr. Sidebotham. Hadlow Down near May- 

 field ; Henfield ; West Chiltington near Pulborough, Sussex ; Hants, Kent, 

 and Surrey, Mr. Jenner. Dolgelley, J. R. 



Falaise, Brebisson. Italy, Meneghini. Germany, Kiitzing. United States, 

 Bailey. 



The frond is exceedingly minute, quite smooth, and constricted at the 

 middle, the constriction causing a linear notch on each side. The segments 

 are nearly quadrate and the sides and end are bicrenate. The transverse view 

 is elliptic. 



Length of frond from ^-^r ^^ TsT ^^ ^^ ^^^^^ 5 breadth from xtto ^^ ttts » 

 breadth at constriction from y-jVr to 3/59 - 



Tab. XV. fig. 6. a. front view ; b. empty frond ; c. transverse view. 



9. C. crenatum (Ralfs) ; frond punctate, deeply constricted at the 

 middle ; segments crenate at the margin and flattened at the end ; 

 spines of sporangia very short. 



Cosmarium crenatum, Ralfs, in Annals of Nat. Hist. v. 14. p. 394. t. 11. 



