SPECIES OF DESMIDS. 97 



d. Basal lobe deeply notched; basal lobule broadly marginate; central 



lobule obtsue multilobatum, 98 



d. Basal lobe undulate (///). 



d. " rounded or angular (/). 



e. Margins smooth (k). 



e. " cuspidate, spinulose or beaded (/). 



/. Basal lobe undulate (w). % 



f. rounded or angular (,r). 



g. Margins smooth (/) 



g. " cuspidate, spinulose or beaded (j). 



h. End lobes horizontal; diam. 45-50;* . . . Nordstedtianum, 105 



h. " diam. 35-40/4 spinosiim, 106 



h. " " upright, diverging formosum, 103 



/. Basal lobes deeply notched (y). 

 /. " undulate (z). 



j. Cytioderm rough with conic granules; semi-cells with one large 

 central inflation, a smaller one on each side, two on end lobe, 



verrucositin, 100 

 d. Basal lobes undulate (cc], 

 k. " rounded or angular (ee). 



I. A short spine on the angles of end and basal lobes divaricatum, 104 

 /. A small projection on each side near the apex . compaction, 107 

 ;;/. Cytioderm more or less tuberculate (;/). 

 m. " punctate (<?). 

 m. " smooth (r). 



?i. Tubercles basal, mostly 5 circulare, 101 



n. 5 central, 4 marginal elegans, 106 



n. " scattered; end lobe with a tooth on each side, 



ornithocephalum. * 



o. Semi-cell 5-lobed, basal lobe emarginate, the lateral small, entire, 



pinnatum, 98 



o. " not 5-lobed (/). 



/. Basal lobe with i lateral, subcentral tubercle, not emarginate, 



amputtaceum, 100 



/. Basal lobe without lateral tubercle, slightly emarginate, affine, 100 

 /. " " " " not emarginate; diam. 22-25^, 



di delta, 99 

 p. " not emarginate; diam. 60-69;^ . . . ventricosum. ** 



*Journ. R. Micr. Soc., Feb., 1886. 



