474 POLYMORPHISM AVD LIFE-HISTORY IN THE DESMIDIACEiE, 



aut rotundatis levissime inflatis, f^ranulis plicisve minutissimis 

 ornatis. Endochroma in lamina unica ut videtur convoluta, ad 

 apicein planam ordinata. 



A. Long. semi. 200; lat. bas.21; constrict.! 2; centr.l4; ap.lG/^. 



B. Long. semi. 244; lat. bas.26; constrict. 16; centr.17; ap.l6/x. 

 Auburn, Guildford. 



A. joined with var. Ehrenhergii, B. with var. Delpontei, the 

 endochrome of the latter specimen not noted. The semicell is 

 the shape of var. baculum, but the basal granules or plicpe are 

 ■wanting, and the size is larger. The interest and importance of 

 the lind lies in the fact that, whereas the endochrome of the var. 

 Ehrenhergii semicell was normal, the part within the basal infla- 

 tions of both seniicells was evidently in the form of a parietal 

 tubular lamina. This portion exhibited the appearance of vertical 

 fibrils, and this slightly supports my contention that the parietal 

 lamina of var. haculum divides vertically into four fillets as the 

 cell develops into var. Ehrenhergii. 



Var. EHRENBERGii(Breb,), forma. (Pl.xii., f.5). 



Forma ad suturam utrinque serie plicarum obscurariim(circ. 

 9-10 visis) ornata. Long. 516; lat. bas.25; constr.21; centr.23; ap. 

 17/x. 



Botany(109A). Cum antecedent!. 



All the forms in 109 had distinctly punctate-scrobiculate mem- 

 branes. The three foregoing all had the same smoothly rounded 

 but truncate apex (Pl.xii., f.8), and showed such an unmistakable 

 similarity that there could be no doubt whatever of their specific 

 identity. Doc. manubrium W. A G. S. West, Frw. Alg. Ceylon, 

 PI. 19, f.ll, and Frw. Alg. Madag., PI. 5, f.31, is simply var. 

 Ehrenhergii and var. Deljjontei in which the basal plicje of var. 

 baculnm have persisted. It should stand as Doc. trabecula var. 

 manubrium. The form here noted is practically the same, but 

 the plicae very faint. What difference is there between Pl.xii., 

 i.\a, and Frw. Alg. Ceylon, PI. 19, f.ll? 



