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of H. pelagica. (With regard to C. Claus’s description of the bristles on the endopodite of the
second antenna G. W. MÜLLER writes, 1906 a, p. 51: ,,Bei der Länge der Borsten des
Nebenastes der 2. Antn. werden sekundäre Geschlechtsmerkmale und Artunterschiede mit Charakteren,
die von einer ganz anderen Art genommen sind, durcheinander geworfen.“ It seems to me
very doubtful whether this statement is correct.) Among the characters adduced by C. CLAUS
the folio wing are variable: First antenna: The proportion between the lengths of the e-bristle
and the a—d-bristles. Second antenna: The proportion between the length of the first exopodite
joint and the total length of the eight distal joints of this brauch. The shape of the clasping
organ on the endopodite of the males (cf. G. W. MULLER, 1906 a, p. 50) and the breadth of the
g-bristle on this branch. With regard to the last character it is, however, to be noted that
I have never found so narrow a g-bristle as in pl. XXII, fig. 5, C. Claus, 1891 a. The length
of the end claws of the fifth and sixth limbs. The type of the frontal organ varied only
rather slightly in the specimens investigated by me; there was not, however, füll constancy.
Variation in this organ was also observed by G. W. Müller, 1906 a, p. 51.
The only one of the differences brought forward by C. CLAUS that really remains after
this thinning is the number of the furcal claws. C. Claus gives eight furcal claws for IL concha,
five for the males of H. pelagica and six for the females of the same species. The uncertainty
as to the statement for the males of H. pelagica has been pointed out above; in pl. XXI, figs. 7
and 11 the furcae of both the male and the female have six claws (or five claws posterior ly ofthe
„Hakenborste“). Curiously enough, I found seven claws constantly on the specimens
investigated by me, i. e. a number between those given for H. concha and H. pelagica. G. AV. MÜLLER
writes, 1906 a, p. 51, as follows with regard to this character: . . . „doch kann ein Schwanken
in der Zahl bei einer Art, die so stark in der Größe variiert, kaum überraschen. Auch dieser
Unterschied scheint mir zur Spaltung der Art ungeeignet.“ Nor do I think it possible to ascribe
any decisive significance to this difference.
It seems to me beyond all doubt that H. brevirostris, G. S. BRADY, 1880 and H. concha,
G. S. Brady and A. M. Norman, 1896 are identical with the form described above, in spite of
a number of differences that are to be noted; see, for instance, the rostrum in pi. XXXIX,
fig. 1, G. S. BRADY 1880 and the sixth limb in fig. 10 of the same plate. These differences are
presumably due to lack of precision on the part of this autlior*.
* It is perhaps vvorlhy of special mention that G. S. Brady succeeded in finding both IL concha and 11. pelagica
on a révision of the Oslracod material of the „Challenger“ expedition. In the above-inentioned work by
G. S. Brady and A. M. Norman il is poiuted out in a note to U. concha, p. 703, lliat „a few specimens oecurred in
tow-net gatherings taken by the „Challenger“ expedition, but were not recognized nor described by Dr. Brady
in his monograph of the Ostracoda“. This shows as far as I can see quite clearly that these investigators did not considor
that H. concha is a synonym of II. brevirostris, G. S. Brady, 1880. But there ean scarcely be any doubt that these
forms are identical. As a curiosity and an example of the uncertainty of the information given by G. S. Brady the
following may be pointed out here: In the above-mentioned work by G. S. Brady and A. M. Norman there is a statement
to the effect that H. concha was caught by the „Challenger“ expedition at three different stations; no locality
where H. pelagica was found by this expedition is mentioned in this work. In G. S. Brady’s work. 1897, II. concha
is stated to have been caught at oidy one station by the „C hallende r“ expedition, while //. pelagica b said to have
been found at two of this expédition’« stations. It is to be noted that the station for II. concha in the latter work
is not identical with any of the three stations for this species given in the work of 1896; on the other band one of the
stations for H. pelagica mentioned in the work of 1897 is identical with one of the stations for II. concha in the work
of 1896. G. S. Brady does not give any explanation of this curions state of affairs in his work of 1897.
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