AMPHORA. I33 



A cymbifera Greg. (Diat. of Clyde, p. 54, pi. 6, f. 97. Ad. 

 Sch. Atl., pi. 25, f. 13, 17-19* ; pi- 26 > f - 33) Plate 24, fig. 678. 



Frustule elliptic, with produced truncate apices ; valves narrow, arcuate 

 with rostrate-capitate apices; ventral margin and raphe almost straight ; striae 

 radiant, robust, 9-12 in 1 c.d.m. Sutural . zona elliptic. Length, very 

 variable, from 5 to io c.d.m. 



Marine. England, Scotland, Ireland, Denmark, Norway, etc. 



A. rostrata W. Sm. (s.B.D. i., p. 20, pi. 30, f. 253*) plate 24, 

 fig. 679. 



Frustules inflated, sub-oval with apices rostrate-truncate showing 

 longitudinal costae marked with a double row of puncta. Valves arcuate 

 semi-lunar with apices capitate : striae robust, 6 to 7 in 1 c.d.m. 



Marine. England (W. Sm. Norman), Scotland (Greg.), Ireland (O'Meara). 



A. angularis Greg. (Q.J.M.S., 1855, p. 39, pi. 4> f. 6 ; h.v.h. 



Atl., pi. 1, f. 21*, Type No. 12) plate 1, fig. 8. 



Frustule panduriform with apices tapering, broadly truncate, connecting 



zone with fine transverse striae, interrupted by numerous pleats. Valves with 



dorsal margin constricted in the middle, apices tapering, acuminate, raphe 



infinitesimally inflexed ; striae punctate, about 18 in 1 c.d.m. Length, 4 to 



5 c.d.m. 



Var. hybrida Grun. (In H.V.H. 's Type, No. 12). Valves with 

 constriction only slightly if at all marked, showing a longitudinal line in the 

 convex part. 



Var. lyrata (A. lyrala Gres,. Diat. of Clyde, p. 48, pi. 5, fig. 82, 

 H.V.H. Atl., pi. 1, fig. 22* ; in Type No. 12) plate 1, fig. 9. 



Differing from the type-form in being shorter (about 3 c.d.m.) and its 

 median constriction being less pronounced, which, when inadequately 

 resolved, slightly resembles a stauros. 



Brackish waters, The type form, and varieties mixed together at Blankenberghe 

 and Antwerp. Scotland, Ireland, Norway. 



A. macilenta Greg. (Diat. of Clyde, p. 38, pi. 4, f. 65*) plate 



24, fig. 680. 



Resembling A. salina. Frustules elliptic, long, narrow, with apices pro- 

 duced, tapering ; valves very delicate, arcuate on dorsal side, ventral margin 

 straight. Raphe very distinct. Striae parallel, rather robust, 12 in 1 c.d.m. 

 Sutural zone very narrow. Length, 4 to 5 c.d.m. 



Marine. Scotland (Gregory) ; North Sea. 



This species is quite unknown to me, and the very poor figure given by Gregory makes it 

 impossible to recognize it. 



