studies on marine Ostracods ' 599 



of H. pelagica. (With regard to C. Claus's description of the bristles on the endopodite of the 

 second antenna G. W. MtlLLER writes, 1906 a, p. 51: „Bei der Lange der Borsten des Neben- 

 astes der 2. Antn. werden sekundiire Geschlechtsmerkmale und Axtunterschiede mit Charakteren, 

 die von einer ganz anderen Art genommen sind, diircheinander geworfen." It seems to me 

 very doubtful whether this statement is correct.) Among the characters adduced by C. Cl^VUS 

 the following 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 branch. 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 pi. XXII, fig. 5, C. ClAUS, 1891 a. The length 

 of the end claws of the fifth and sixth limbs. The tyipc of the frontal organ varied only 

 rather slightly in the specimens investigated by me; there was not, however, fuU constancy. 

 Variation in this organ was also observed by G. W. MOller, 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 H. 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 pi. XXI, figs. 7 

 and 1 1 the f urcae of both the male and the female have six claws (or five claws posteriorly of the 

 ,,Hakenborste"). Curiously enough, I foimd seven claws constantly on the specimens investig- 

 ated by me, i. e. a number between those given for H. concha and H. pelagica. G. W. MULLER 

 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 GroBe variiert, kaum iiberraschen. 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. Xorman, 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 author*. 



* It is porhaps woilliy of special niunlioii thai G. S. Brady smxoudfd in liadiiijj both JJ. cunclia and Jl. pelagica 

 on a revision of the Oslracod material of the ,,C h a 1 1 e n g c r" expedition. In the above-monlioned work by 

 G. S. Brady and A. M. Norman it is pointed out in a note to //. concha, p. 703, Ihal ,,a few specimens occnrrod in 

 tow-net gatherings taken by tiio ,,C h a 1 1 e n g e r" expedition, but were not recognized nor described by Dr. Bhadv 

 in his monograph of llu! Os(raco(ia". This shows as fai- as I can sec quite clearly Ihal these investigators did not considiT 

 that //. concha is a synonym of H. brevirostris, G. S. Brady, 1880. Bnl tliere can scarcely be any doubt Ihal these 

 forms are identical. As a curiosity and an example of the uncertainty of the inforntation 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 //. concha was caught by the ,,C h a 1 1 e n g e r" expedition at three different stations; no locality 

 whore H. pelagica was found by this expedition is mentioned in this work. In G. S. Brady's work. 1807. //. concha 

 is stated to have been caught at only one stiilion by the ,,C h a 1 1 e n g e r" expedition, while //. pelagica is said to have 

 been found at two of this expedition's stations. It is to be noted that the station for //. 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 hand one of the 

 stations for //. pelagica mentioned in the work of 1897 is identical with oi\e of the stations for //. concha in the work 

 of 1896. O. S. Brady does nol give any explanation of this curious stale of affairs hi his work of 1897. 



