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Second antenna: — The b-bristle on the first joint of the endopodite had in
one specimen two, in the other three long hairs.
Sixth limb: — Thç endopodite had two bristles, one oî which was rather short.
Exopodite: The first joint had one short dorso-distal bristle and one rather short bristle at
about the middle of the ventral side.
Are we concerned here with two closely related forms, which were confused by G. A’.
MÜLLER, 1906 a, or is C. spinirostris a species with a relatively great amplitude of variation?
In answering this question the following remark of G. A’. MULLER, 1906 a, p. 105, lias
a certain interest: ,,Ç von über 1,4 und S von über 1,3 fanden sich nur in Station 32—55, wo die
Thierè überhaupt im Durchschnitt größer.“ In the samples investigated by this writer the large
and small specimens were tlius not mixed up together quite without any principle; on the
contrary, at the sixteen stations at which large specimens were caught no small specimens were
found, nor were any large specimens fourni at the 36 stations where the plankton samples
con-tained small specimens. The stations in question, nos. 32—55, are situated in the Atlantic
from lat. 24° N. and lat. 2° N.; the depths are only known in two cases, 42 S. 550—250 m.;
48 S b 280—130 m. To judge from the latter Statements it does not seem probable that this
difference in size between the specimens investigated is due to external conditions. It is also
to be noted that at S. A. E., PI. Station 4 b no small specimens were found, and that no large
specimens were found at those stations of this expedition from which the small specimens
de-scribed by me above came.
G. W. Müller, in his work of 1906 a just mentioned, put forward the assumption that
C. porrecta C. CLAUS was a synonym of C. spinirostris. „Ich halte C. porrecta Claus nur für
gestreckte Individuen von C. spinirostris.“ (The identification was not based on a re-examination
of C. ClaüS’s original material, as is shown by a statement on p. 105 in the work quoted.) It
is certain that these two forms are very closely related to each other. According to the description
and figures C. porrecta differs from C. spinirostris chiefly in the following characters: Length
of shell: 1,6 mm. (this statement, like, as a matter of faet, the whole description of the shell,
certainly refers to female specimens). Male first antenna: The a-bristle is relativelv short,
reaching only to about the boundary between the first and second joints of this limb. E-bristle:
,,.... mit sehr zahlreichen, wohl 40—50 Paaren von Häkchen besetzt, von denen die 14—16
distalen Paare viel dicker und dichter gestellt sind, die nach der Basis zu folgenden in weiteren
Zwischenräumen stehen und zu Stachelborsten werden.“ (The b-bristle on the first endopodite
joint of the male second antenna is not mentioned or reproduced b}’ this writer.)
If we assume that C. CLAUS made a mistake in observation (which does not seem to me
improbable on account of the uncertainty that ölten eharacterizes the Statements as to details
given by this writer) and there was not a double but only a single row of spines on the e-bristle
of the male first antenna proximally of the fourteen to sixteen distal pairs of spines, then the
agreement between the information given by this writer for C. porrecta and G. \V. MÜLLER’s
description of C. spinirostris, 1906 a, becomes almost complete. The latter writer gives no
information as to the a-bristle on the male first antenna. The specimens investigated by me
from S. A. E., PI. station 4 b agreed in this respect with C. Ci.aus’s statement in the case of
K9
Zoolog, bitlntg, Uppsala. Suppl.-IM. I.
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