100 SPECIES OF DESMIDS. 



c. Semi-cells 5-lobed (/;/). 



c. Semi-cells 3 or obscurely 5-lobed; lateral sinus shallow, obtuse; 



lateral angles mucronate decemdentata, 113 



d. Basal lobes with 3 linear processes on each side . muricata, 118 



d. " without linear processes, but (e). 



e. Forked once only, margins fine!)* serrate, Mahabuleshwarensis, 112 

 e. " " " margins and surface spinous . . . sptnosa.** 

 e. " " " margins smooth .... Nordstedtiana, 113 

 e. Forked twice (lobules forked); cytioderm spinous . . spinosa* 

 e. " cytioderm smooth; margins serrate, Hermanniana, 112 



e. " " " margins not serrate, Americana, 112 

 /. End lobe nearly as wide as the basal, apices deeply notched (g). 

 /. " " " " " apices not deeply notched (//). 



f. End lobe much narrower than the basal, end convex, oscitans, 116 



f. " " " " " " end deeply emarginate, 



foliacea, \ \ 8 

 /. " " " " " " end slightly concave, 



Rabeuhorstii. * * 



g. Basal lobes furcate (with lobules), (/). 

 g. " not furcate (/). 



h. End lobe convex, without prominences laticeps, 115 



//. " truncate, with 2 small prominences .... recta, 112 



h. " retuse, basal lobe furcate Baileyi, 118 



/. " with 2 slender, transverse, bidentate projections, 



quadrata, 117 



i. End lobe without projections, convex; sinuses broadly rounded, 



Kitchell ii, 1 16 

 /. " without projections, concave; neck short; sinuses acut- 



ish Rabenhorstii, 118 



/. " " " k< neck long; basal lobes 



curved upwards simplex* 



j. Basal lobes horizontal, not curved pinnatifida, 116 



/ " curved upward, narrow, 



expansa, 1 1 7 ; arcitata, \\i\simplex* 



k. Basal and lateral lobes deeply furcate (with lobules), furcata, in 

 k. " " " shallowly furcate, surface smooth, (") 



k. " surface spinous; diam., 



175-200^ apiculata** 



h. " " not furcate . . . pseudofurcata, 1 1 1 



* Journ. R. Micr. Soc., Dec. 1885. 

 ** F.-w. Algre, p. 36 et seq. 



