JS P. T. CLEVE, DIATOMS FROM BAFFINS BAY AND DAVIS STRATIT. 
verging at an acute angle, with spirally arranged small 
puncta. Endocysts with dissimilar valves, the one slightly 
convex or conical, unarmed, and the other more convex and 
covered with many spines, branching at the top. Dimensions: 
long. ax. 0,012 to 0,02; sag. ax. 0,02 to 0,04; transv. ax. 0,01 
0 OO men, — IPL IL RK 
This form which I cannot identify with any other de- 
seribed species resembles in sagittal view C. curvisetus, but 
the awns have a different direction. It occurs in large mas- 
ses in the plankton of Baffins Bay from the beginning of 
August. 
Var. leptopus CL. — Chains of a few frustules only, their 
terminal awns filiform and curved inwards. Foramina narrow 
panduriform. Dimension: long. ax. 0,02 to 0,o24; sag. az. 
0,06; transv. ax. 0,014 mm. Endocysts as in the type, but 
larger. — PI. II, 5. 
Chzetoceros Mitra (Barn.) C1. — Chains straight, solid, 
multicellular. - Foramina narrow, slightly panduriform to 
narrow elliptical, shorter than the cellules. Cellules in sa- 
gittal view almost quadrate, with slightly protracted angles; 
in transversal view elliptical. Valves concave. Dimensions: 
long. ax. 0,032; sag. ax. 0;038; transv. az. 0,024 mm. Awns 
marginal, their basal part short, their prolongations almost 
straight, in the sagittal view diverging in a right angle. 
Terminal awns stronger than the others, with spirally ar- 
ranged puncta, obsoletely transversely striate. Endocysts 
with very different valves, one flat, and the other elevated 
to two large cones, having at the top a branched silieious 
awn; in transverse view elliptical. Sag. ax. 0,04; transv. ax. 
(019 mim SE === US 
Syn. Dicladia mitra Bain, D. groenlandica Cr. (Diat. 
OT, FENG aret sea pater bl EO 
The endocysts have been known for long and are widely 
distributed in the polar seas. They occur abundantly in the 
Cape Wankarema material, on the iceflakes, drifting along 
the east coast of Greenland. It is sometimes found in a 
fossil state in the Baltic deposits of the Litorina-epoch. In 
Baffins Bay it appears in the middle of August and continues 
to the end of September. It was not observed in the Davis 
Strait plankton, collected in October. All appears to show 
that this characteristic form is derived from the polar seas. 
