TETMEMOTUTS. 223 



Sandwich Islands (var.). A /ores. United Stales. 

 Dominica and Trinidad, W. Indies. Brazil. 



This small speeies of the o-enus is almost as generally dis- 

 tributed ;is T. (ir(i)iiilntns, and at lii^h elevations is often 

 niiicli more abundant. The median constriction is often \ cry 

 faint, and the semicells are not so attenuated as those of 

 T. </rri))i<ltitN ; the zygospore is also peeuliar. The cell-wall 

 is always minutely punctate, sometimes move distinctly than 

 at others. 



T. Ar/v.s- has a world-wide distribution; it is found from 

 sea-level to the snow-line, and also in the waters ot warm 

 and hot springs. It is rarely found in the freshwater 

 plankton. 



4. Tetmemorus minutus De Bary. 

 (PL XXXII, figs. 17-ID.) 



DP Bary, Conj. 18.18, p. 41, 74, t. 5, f. K) ; Arch, in 

 Pi-itch. Infus. 1861, p. 746; Eabenh. Flor. Europ. Al^ar. Ill, ]S<;s, 

 p. 140; Kivchn. A !_;. Schles. 1878, p. 145 ; Hansy. Prodi- . Ali;-cnn. Bi)liin. 

 isss, p. 189; Do' Toiii, Syll. Alg-. 1889, p. s<s : I!-nn. Freslnv. Al-\ 

 S.W. Surrey, ]S<)2, p. 5 : Roy & Bis's. Scott. Desm. 1894, p. 242 ; Novdst. 

 Index D.-siii. is'.Ki, p. 172- West & G. S. West, Alga-fl. Yorks. Him. 

 p. 60. 



Cells small, about 3 times longer than their diameter, 



witli n slight median constriction ; semicells conspic- 

 uously attenuated from base to apex; apices with a 

 deep median incision ; cell- wall delicately and some- 

 what sparsely punctate ; cliloroplasts with one or two 

 pyrenoids; semicells in the side view rather more 

 attenuated than in the front view. 



Zygospore unknown. 



Length 52-65 /x ; breadth 1!)- 1 21 ^ ; breadth of 

 isthmus 1S'5 //,. 



ENGLAND. Dodd Fell, N. Yorks. (at 2,000 ft,)! 

 Hindhead, Surre^v (Jlciturft). 



WALKS. Capel ( 1 urig (#<>//), Pen-y-gwryd (//"//), 

 and Llyn Bochlwyd ! , Carnarvonshire. Radnorshire ! 



SCOTLAND. Not uncommon on wet rocks (//<>// \ 

 ///.s-.sv//). Moidart, Inverness! (Jciieral throughout 

 the Outer Hebrides ! 



IIMILAND. Dublin and Wicklow 



