ill!Ill

f Carinal dots prolonged .
HANT2SCHIA. $&l
ANALYSIS OF SPECIES.
into costte, which traverse the entire valve
Carinal dots ( Carinal dots slightly prolonged . . H.
slightly
or not <
prolonged. ( Carinal dots not prolonged .
H.
marina.
virgata.
. . H. amphioxys.
H. amphioxys (Ehr. ) Grun. (Arct. Diat, p. 103; Nitzschia
amphioxys, IV. Sm., S.B.D., L, p. 41. pi. 13, f. 105 ; H.V.
and 2*; Type No. 367), plate 15, fig. 483/'.
H. Atl., pi. 56, f. 1
Valves feebly arcuate, with apices more or less prolonged. Keel with
coarse short dots, about 7 in 1 c.d.m., the two median distant. Striae about
16 in 1 c.d.m. Length (very variable), about 4*5 or 7-5 c.d.m.
Fresh and brackish water Frequent. England (Kitton, W. Sm., Norman). Ireland (O'Meara).
var. major. (H.V.H. Atl., pi. 56, f. 3 and 11*), plate 15, fig. 484/'.
Much larger, about 12 c.d.m., with 5 to 6 carinal dots, and about 11
striae in 1 c.d.m.
var. intermedia. (H.V.H. At!., pi. 56, f. 4*), plate 15. fig. 485/;.
Pfean length, about 8 c.d.m., with 4 carinal dots, and about 11 striae
in 1 c.d.m.
var. vivax. (Nifzschi'i vivax Hanizscli non IV. Sm. ; H.V.H. Atl.,
pi. 56, f. 5 and 6*; Type No. 368), plate 15, fig. 486/;.
Valve slender, longly rostrate ; about 5 carinal dots and 13 striae in 1
c.d.m. Length,
10 c.d.m.
Brackish water. England (Kitton).
var. elongata. (H.V.H. Atl., pi. 56, f. 7 and 8*), plate 15, fig. 487/-.
Length, up to 22 c.d.m.; strongly rostrate and genufiexed ; 7
carinal dots, and 17 striae in 1 c.d.m.
or 8
H. virgata (Roper) Grun.! (Arct. D., p. 104; H.V.H. Atl.,
pi. 56, f. 12 and 1 3* ; Type
No. 370), plate 15, fig. 488/'.
Valve robust, arcuate, with apices strongly rostrate, rostrum obtuse >
Keel with 4 or 5 dots in 1 c.d.m., dots prolonged into short costae on the
valve. Striae, 9 to 11 in 1 c.d.m. Length, about 13 c.d.m.
Marine. Blankenbcrghe (H.V.H.), washings of mussels (Deby.), France (Breb.), England
(Roper, Kitton, Comber, Stolt, Norman), Ireland (O'Meara).