138 AMPHORA. 



A. bacillaris Greg. (Diat. of Clyde, p. 55, pi. 16, f. 100*), plate 

 24, fig. 689. 



Frustule linear, narrow, with apices slightly rounded, subacute. Valve 

 with ventral portion narrow, striation finer than that of the dorsal portion. 

 Raphe slightly inflexed. Connecting zone narrow on ventral side, very large 

 on dorsal side of frustule and showing 7 or 8 narrow segments. 



Marine. Scotland (Gregory). 



A. ArCUS Greg. (Diat. of Clyde, p. 50, pi. 13, f. 88*), plate 24, 

 fig. 690. 



Frustule subquadrangular, with outer margins infinitesimally inflated as 

 far as the central portion, with truncate apices. Valves narrow, with ventral 

 margin infinitesimally arcuate, ventral margin and raphe inflexed, apices 

 strongly rostrate, slightly capitate. Stripe robust, moniliform, 6 to 7 in 1 c.d.m., 

 Sutural zone showing 16 to 17 robust bars formed by the ventral margins 

 being approximate to juxtaposed segments. Length, 9 to 10 c.d.m. Breadth, 

 up to 5 c.d.m. 



Marine. England (W. Sm. Greg., Norman) ; Scotland (Greg). 



A. lineolata Ehr. {Navicula lineolata Ehr. Inf., p. 188, n. 250 

 pi. 14, f. 4 ; A. tenera, W. Sm., S.B.D., i., p. 20, pi. 30, f. 252, H.V.H., Atl. 

 pi. 1, f. 23*; Type No. 6); plate 1, fig. 10. 



Frustule elliptic-oblong, inflated at the median portion, infinitesimally 

 attenuate up to the apices which are slightly rounded. Valves with raphe 

 considerably inflexed, with striae finely punctate, about 23 in 1 c.d.m. 

 Connecting zone with very fine transverse strioe, interrupted by numerous 

 longitudinal pleats. Length, 4 to 5 c.d.m. 



Fresh and brackish water. Blankenberghe ; England (W. Sm. ! ) 



A. hyalina Klltz. (Baa, p. 108, pi. 30, f. 18 ; S.B.D., i., p. 19, pi. 2, 

 f. 28 ; Ad. Sch. Atl., pi. 26, f. 52-55*) ; plate 24, fig. 691. 



Frustule slightly silicious, hyaline, very broadly elliptic, with apices slightly 

 truncate. Valve very broad, with very convex dorsum. Ventral margin and 

 raphe straight. Valves rather strongly striated longitudinally, with striae 

 parallel to the dorsal curvature. Transverse striae excessively fine. Length, 

 5 to 8 c.d.m. 



Brackish. England (W. Sm, ! Norman, Stolterfoth) ; Ireland (O'Meara) ; France ; Germany ; 

 Denmark ; Norway, etc. 



