ill!Ill

160 STAUR0NE1S.
tabular, showing the thickening of the internal apices
connecting zone plicate-punctuate. Length, 8 to 15 c.d.m.
Fresh water. Everywhere, but not so frequent as St. Phcenicenteron.
of the valves and the
S. Gregorii Ralfs. (in Pritch., p. 913. S. amphioxys Greg, T.M.S.,
1856, p. 4S, pi. 5, f. 23 ; H.V.H. Atl., Suppl. f. 4* ; in Types No. 74 and 389) ;
plate 1, fig. 52.
Valve lanceolate, with apices subrostrate ; more or less obtuse and show-
ing ;
a rather small lumen raphe
simple ; stauros very broad ; striae finely
granular, slightly radiant, delicate, about 18 to 20 in 1 c.d.m. Length, about
8 c.d.m.
Brackish water Biankenberghe (rare?). England (Kitton). Scotland (Greg.).
** Stauros very narrow, raphe simple.
S. Spicula W. J. Hickie. (Monthly Micro. Journ., 1874, xii.,
p. 290; H.V.H. Atl. pi. 4, f. 9* :
in Type No. 9), plate 1, fig. 53.
Valve very narrowly lanceolate, infinitesimally attenuate as far as the
subacute apices ; stauros very narrow, not dilated at the extremities ; raphe
simple, surrounded by a narrow hyaline zone ;
28 in 1 c.d.m. Length, 5
to 8 c.d.m..
striae delicate, scarcely radiant,
Brackish water. Very rare? Antwerp, Biankenberghe. England, Swansea Dock (Okeden
in H.V H., Type No. 9), Norfolk (Kitton).
S. salina W. Sm. (s.B.u. i., p. 60, pi. 19, f. 188; h.v.h. Atl.,
pi. 10, f. 16*; Type No. 44), plate 1, fig. 54.
Valve rather broadly lanceolate, with apices sometimes slightly produced-
rostrate ; stauros narrow, only slightly or not enlarged at extremities ; stria?
delicate, finely punctate, scarcely radiant, about 18 in t c.d.m. Length, about
5 to 6 c.d.m. ; breadth, 0.5 c.d.m.
Marine. Biankenberghe, Antwerp, England, Ireland, Denmark.
b. VALVES WITH APICES ROSTRATE OR ROSTRATE-CAPITATE.
S. ancepS Ehr. (Verb., p. 134, pi. ii., 1, 18; H.V.H., Atl. pi. 4,
f. 4, 5*; Type No. 43), plate 1, fig. 55.
Valve elliptical or elliptical-lanceolate, with apices rostrate-capitate ;
stauros
broad, dilated near its extremities ; raphe simple, surrounded by a broad
hyaline zone; striae delicate, strongly radiant, about 20 in 1 c.d.m.; length,
3.5 to 5 c.d.m.
Fresh water. Everywhere (but not very abundant?).
Var. linearis. (S. linearis KUtz. H.V.H. Atl., pi. 14, f. 8*); plate i,
fig. 56.
Valve with parallel margins ; apices abruptly attenuate-rostrate.