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. MtJLLER writes, 1906 a, p. 61: ,,Bei der Lange der Borsten des Neben- 

 astes der 2. Antn. werden sekundare 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 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. MOller, 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 type of the frontal organ varied only 

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

 Variation in this organ was also observed by G. W. MtJLLER, 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 11 the furcae of both the male and the female have six claws (or five claws posteriorly of the 

 ,,Hakenborste"). Curiously enough, I found 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. MtJLLER 

 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. 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 author*. 



* IL is pcrliaps worth)' of -speuial niciiUuii thai (i. ti. Brady succcedi^d ia liiidiiig Ijoili //. concha and Jl. //clagtca 

 on a revision of the Ostracod material of the „C h a 11 e n g e r" expedition. In the above-mentioned work by 

 G. S. Brady and A. M. Norman it is pointed onl in a note to //. concha, p. 70;i, that ,,a few specimens ocenrred in 

 tow-net gatherings taken by llie ,,C h a 1 1 e n g e r" 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 consider 

 that H. concha is a synonym of H. brevirostris, G. S. Brady, 1880. But there can 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 l)e 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 „C h a 11 e n g e r" oxpcdilion at three different stations; no locahty 

 where //. pelagica was found by this expedition is mentioned in this work. In G. S. Brady's work, 1897, //. concha 

 is staled to have been caught at only one station by the „C h a 1 1 e n g e r" expedition, while H. 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 H. pelagica mentioned in the work of 1897 is identical with one of the stations for H. concha in the work 

 of 1896. G. S. Brady does not give any explanation of this curious state of ;iffairs in his work of 1897. 



