BIHANG TILL K. SV. VET.-AKAD. HANDL. BAND 22. AFD. III. N:05. 29 
basal part 0.oo4 mm., parallel to the longitudinal axis. In 
transverse view the awns are curved outwards and diverge 
at an obtuse angle, finally nearly parallel to the transverse 
axis. Terminal awns stronger then the others, slightly di- 
verging, denticulate on their exterior parts. — Emndocysts with 
dissimilar valves, one being bell-shaped, the other nearly 
fat, or slightly conical, unarmed. — Fig. 9, 11. 
« Syn. Ch. distans Cr. in Bih. t. K. Sv. Vet.-Akad. Handl. 
RO era pod PIE, fog. 
Marine: West-coast of Sweden (November 1893, February 
1896). West-coast of Scotland. 
I have previously confounded this species with Ch. di- 
stans CL. from Java, which has some resemblance, but is 
stronger and more silicious. 
Fig. 10 a, b, c represent endocysts of specimen from Scot- 
land, mounted in balsam, fig.11 an endocyst, probably also of this 
species, found in plankton from Kattegat. It is remarkable 
for its fine hairs, but having found this endocyst without 
connection with the cellules, I am somewhat uncertain whether 
it really belongs to this species. Fig. c represents a cellule 
in transverse view, from Scotland. 
Chaetoceros contortus ScHötT (Ber. d. Deut. Bot. Ges. 
1895, XIII, 44). This form, which I have formerly confounded 
with Ch. compressus LAUDER (Bih. XX, 3, 2, 12) differs from 
the last by its cellules, being orbicular in the transverse view, 
and by the twisted chains. 
Chaetoceros criophilus Castr. (Voy. Challenger. Diat. 
p- 78) found previously in the antarctic ocean, seems to be 
nearly related to Ch. peruvianus BIW., which occurs in iso- 
lated cellules, Ch. criophilus forming short chains. 
Ghetoceros curvisetus CL. Endocysts lenticular, with 
dissimilar valves, the more convex having on its top a group 
of spines, dichotomously branched at their ends. Dimensions: 
long. ax. 0.008; sag. ax. 0.03 mm. — Fig. 12. 
a Chaetoceros danicus CL. This species occurs in the 
plankton of Bornholm in short chains, which have some res- 
semblance to C. borealis. 
