ill!Ill

326
FRAGILARIA.
var. binodis Grun. (H.V.H. Atl., pi. 45, f. 24A. and 25*), plate
11, fig. 452.
Valve lanceolate, with apices rostrate, median portion constricted.
Fresh water. Antwerp, rather common and parasitic on Nitzschia Sigmoidea. Ard.
Lieg. (De Wild.). England (Kitton), &c.
F. tenuicollis Heib. (Consp. Diat. Danic, p. 62, pi. 5, f. 13*),
plate 30, fig. 843 and 843 bis.
Valves very narrowly lanceolate, linear, with apices rostrate-capitate.
Pseudo-raphe narrow ; stride very robust, somewhat radiant, convergent,
approximate, about 10 in 1 c.d.m. Girdle face quadrangular, very elongated,
somewhat produced at the apices. Length, 2*5 to 5 c.d.m.
Fresh water. Denmark (Heiberg). Ireland (O'Meara).
var. intermedia (Fr. intermedia Grun. ; H.V.H. Atl., pi. 45, f. 9*),
plate 30, fig. 844.
Only differs from the preceding by the presence of a small median
unilateral hyaline space. Striae robust, 9 or 10 in 1 c.d.m.
Freshwater. England, Ormesby Broad, Norfolk (Kitton in W. Arn. Coll., Nos, 914-915
tinder the name of Frag, tenuicollis. )
F. Harrisonii (W. Sm.) Grun. ! (Oest. Diat, p. 368; H.V.H.
Atl, pi. 45, f. 2S* ; Type No. 316), plate 11, fig. 453.
Valve sub-cruciform, with rounded angles, apices obtuse or sub-obtuse.
Pseudo-raphe lanceolate. Striae very robust, 4 or 5 in c.d.m, formed of
puncta, confluent and simulating costae. Length, about 2 to 5 c.d.m.
Fresh water. Very rare. Mountainous parts of Belgium : Bouillon (Delogne). England
(W. Sm, Kitton), New River (Grove).
F. mutabilis (W. Sm.) Grun. ! (Oest. Diat,, p, 369, H.V.H.
pl. 45, f. 12* ; Type No. 315), plate 11, fig. 454.
Valves elliptic or, more rarely, linear-elliptic ; striae very robust, with
beads confluent, 8 or 9 in 1 c.d.m. Length, 1 to 2*5 c.d.m.
Fresh water. Brussels (Delogne) Louvaine (P.G.) Ard. Lieg. (De Wild.). England (Kitton),
New River (Grove).
F. brevistriata Grun. ! (H.V.H. Atl, pi. 45, f. 32*; Type No.
31S), plate 11, fig. 455.
Valve lanceolate, with apices produced rostrate ; striae very short and
marginal, 13 or 14 in 1 c.d.m. Length, 1*25 to 2 c.d.m.
Fresh water. Brussels (Delogne). Ard, Lieg. (De Wild.).