ill!Ill

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
far as the central portion, with truncate apices. Valves narrow,
inflated as
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
in 1 c.d.m.
considerably inflexed, with striae finely punctate, about 23
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.
)