296 



EPITHEMIA. 



E. gibba Kutz. (Baa, pi. 4, f- 22 ; H.V.H. Atl., pi. 32, f. 1 and 2* ; 

 Type No. 256), plate 9, fig. 35 2 a , b - 



Valve linear, seen with difficulty, with pseudo-raphe bordered on each 

 margin with a row of coarse beads (extremities of costs ?). Frustule always 

 placed on its girdle face, with its dorsal margin showing in the middle of the 

 median inflation a small inflexion, with a central nodule distinctly visible. 

 Ventral margin straight, but arcuate at the apex. Costs, about 6 or 7 in 1 

 c.d.m., parallel, except at the apices of the valve where they are radiant ; striae 

 finely moniliform, about 14 in 1 c.d.m. Length, 8 to 25 c.d.m. 



Fresh water. Very common everywhere. 



var. parallela Grun. (H.V.H. Atl., pi. 32, f. 3*), plate 9, fig. 353. 



Dorsal and ventral margins parallel, without any inflation. 



var. ventricosa. (E. ventricosa Kiitz. (Bac, pi. 30, fig. 9; H.V.H 

 Atl., pi. 32, f- 4 and 5*; Type No. 257), plate 9, fig. 354. 



Valve short, and strongly inflated at the median portion. 



Mixed with the type, and common. 



* * At least four stricz between two consecutive costce. 

 A. Costae scarcely radiant, beads very robust. 



E. ArgUS KlltZ. (Bac, pi. 29 ,f. 55 ; H.V.H. Atl., pi. 31, f. 15, 16, 

 and 17*; Type No. 255), plate 9, fig. 355. 



Valve with dorsal margin slightly arcuate, ventral margin almost straight, 

 apices very obtuse ; costae very robust, only just radiant, 1 or 2 in 1 c.d.m ; 

 striae gently radiant, finely moniliform, 12 to 14 in 1 c.d.m., more than 

 four striae between two consecutive costs. Girdle face linear, with margins 

 straight or undulated as a monstrosity (see pi. 9, f. 355 at extreme right), 

 showing throughout the length of the connecting zone a series of coarse 

 nodules, arising from the thickening of the apex of the costs. Length, 4 to 

 7 c.d.m. 



Fresh mater in calcareous regions. Frahan (Delogne). England (Comber, Norman). Scotland 

 (Dickie). France, Holland. 



var. amphicephala Grun. (E. Alpestris IV. Sm.; H.V.H. Atl, pi. 

 31, f. 19*), plate 9, fig. 356. 



Valve gently arcuate, with apices strongly rostrate capitate. 



Fresh water. England (W. Sm., Comber, Norman). 



E. Zebra (Ehr.) Kutz. (Bac, pi. 5, f. 12, and pi 30, f. 5 ; H.V.H. 

 Atl., pi. 3 t, f. 9, n, 12, 13, and 14*; Type No. 253), plate 9, fig. 357. 



Differs especially from the preceding species by the girdle face not 

 showing costs inflated at the apices. Costs less robust, scarcely radiant, 3 or 



