CYMBELLA. 1 43 



Valve very elongate, with dorsal margin much more arcuate than 



ventral margin. 



C. subaequalis Grun. ! (H.v.h. Atl., pi. 3 , f. 2; Suppl. f. i* ; 

 Type No. 29); plate 1, fig. 26. 



Valves almost symmetrical, oblong-lanceolate, slightly attenuate, with 

 apices obtuse, rounded, sub-capitate, ventral margin very slightly less arcuate 

 than the dorsal margin ; raphe almost straight, surrounded by a hyaline zone 

 rather broad, and dilated round the central nodule ; striae very radiant, finely 

 punctate, about 10 in 1 c.d.m. in the middle of the valve, 14 near the apices. 

 Length 4 c.d.m. 



Fresh water. Botanical Gardens, Brussels (Del.) ; Ard. Liege. (De Wild.) 



[According to Professor Cleve, this form should really constitute the 

 C. pequalis of W. Sm.] 



C. obtusa Greg. ! (q.j.m.s., 1856, p. 5, pi. 1, f. 19; h.v.h. Atl., 



pi. 3, f. ia*; in Type No. 257); plate 1, fig. 27. 



Valves lanceolate, with dorsal margin inflated, infinitesimally attenuate ; 

 ventral margin almost straight, slightly inflated in the middle ; raphe straight, 

 a little flexuous, surrounded by a slight hyaline zone, very slightly dilate on 

 the dorsal side round the central nodule. Median stria 12, terminal 15 in 

 1 c.d.m. Length about 3 c.d.m. 



Fresh water. Mot yet found in Belgium ; Scotland (Gregory) ; England (Norman.). 



C. pusilla Grun. ! (in Ad. Schm. Atl., pi. 9, f. 36, 37 ; H.V.H. Atl., 

 pi. 3, f. 5* ; in Type No. 12) ; plate 1, fig. 28. 



Valves very lanceolate, with apices very attenuate, slightly obtuse ; dorsal 

 margin very arcuate, ventral margin almost straight, very slightly convex in 

 the median part ; raphe straight, surrounded by a narrow hyaline zone not 

 dilated in the middle. Median striae 14, terminal 16 in 1 c.d.m., finely 

 punctate, Length about 3 to 4 c.d.m. 



Brackish water. Blankenberghe (H.V.H.); Ard. Liege. (De Wild). 



C. delicatula Kutz. (Spec. Aig., pi. 59,11. 13; h.v.h. Atl., pi. 3, 



f. 6* ; Type No. 31) ; plate 1, fig. 29. 



Valves narrowly lanceolate, divided very unequally by the raphe, with 

 apices produced-rostrate ; dorsal margin considerably arcuate, ventral margin 



