CYM BELLA. 



M7 



size. Stride about 7 to 8 in 1 c.d.m. distinctly moniliform with granules 

 small, approximate. Frustules stipitate in living state. Length, 8 to 15 

 c.d.m. 



Fresh water. Very common. 



C. Cymbiformis Ehr. (Cocconema cymbiforme Ehr. Abh., 1835. 

 Inf. p. 225, pi. 19; H.V.H. Atl., pi. 2, f. 11, a.b.c.*; Type No. 22), plate 

 1, fig- 38. 



Valve with dorsal margin slightly arcuate, ventral margin slightly concave, 

 a little inflated in the middle ; apices obtuse-rounded, sometimes somewhat 

 produced. Raphe surrounded by a narrow hyaline zone, slightly inflated near 

 the central nodule, and showing there an isolated punctum, unilateral 

 (omitted in the figure) ; raphe slightly arcuate, with its convexity turned 

 towards the dorsal margin as far as the central nodule, where it is abruptly 

 inflected towards the ventral margin ; striae about 8 in 1 c.d.m., coarse, very 

 finely divided cross-wise. Frustules stipitate. Length, 5 to 10 c.d.m. 



Fresh water. Not so common? Belgium, England, France, Norway, etc. 



/j. parva. (Cocconema parvum, W. Sm.) (H.V.H. Atl., pi. 2, f. 14*, 

 Type No. 23), plate 1, fig. 39. 



Smaller and often more inflated, with apices generally slightly produced- 

 rostrate ; striae as in the type form, but not so distant near the central 

 nodule. Length 3 to 5 c.d.m. 



Freshwater. Rather common ? Belgium, England, Ireland. 



(b.) STRIATION INTERRUPTED BY A BROAD HYALINE SPACE ON THE 

 VENTRAL SIDE OF THE VALVE. 



C. Cistula Hempr. (Cocconema Cislula Ehr. Inf., p. 224, pi. 19, 

 f. 7 ; H.V.H. Atl., pi. 2, f. 12-13*, Type No. 24 var. curta ; Type No. 25), 

 plate 1, fig. 40. 



Valve with dorsal margin very arcuate, median portion strongly gibbous, 

 ventral margin slightly concave, inflated in the middle ; apices obtuse- 

 rounded ; raphe regularly bent, surrounded with a rather broad hyaline zone 

 and strongly inflated near the central nodule on the ventral side ; the diiated 

 portion showing from 2 to 5 isolated granules; striae 7 to 8 in 1 c.d.m.; 

 very robust, finely divided cross-wise. Length, 5 to 9 c.d.m. Frustule stipitate. 



Fresh water. Rather common, England, West Ireland. Prance, Belgium, Holstein, etc. 



/?. maculata. (C. maculata Kiilz. nee Breb. ; H.V.H. Atl., pi. 2, f. 16, 

 17*), plate i, fig 4t. 



Ventricose, with the isolated granules generally absent. 



Fresh water. Rather common, like the type form. 



