316 Miscellaneous. 



form of the sternal portion of the corresponding segment approach 

 the arrangements existing in the other sex. 



However, it must be remarked that in the case of the Palaemons, 

 as in the other previously studied cases of parasitic castration, there 

 is a very singular want of uniformity in the phenomena observed. 

 Thus a specimen of the male Palcemon serratus of the shores of the 

 Channel, infested by Boprjrus squillarum, has very distinctly re- 

 tained the attributes of its sex, and even presents only a slight 

 reduction of the appendix masculina. Perhaps this diversity in the 

 extent of the modifications observed is to be ascribed to the more 

 or less early period of infestation. Moreover, these modifications 

 are not indelible, so far as I may judge from experiments made at 

 the Laboratory at Wimereux iiijon male Pu(juri castrated by 

 Pliryxus p)aguri ; when subsequently freed from their parasites the 

 characters of the male sex gradually reappeared at the successive 

 moults. 



The numerous species of Hippolyte which abound in the arctic 

 seas are often infested by Bopyrians confounded by authors under 

 the collective names of Oyge hippolytes, Kroyer, and Phryxus abdo- 

 minalls, Kroyer. Hitherto I have not been able to study a suffi- 

 cient number of these parasites ; but a careful examination of the 

 synonymy leads me to think that they exert the same action upon 

 the Hippolyte as the Bopyri upon the Palcemon. In fact, among 

 the numerous species of Hippolyte established by Kroyer and the 

 zoologists of the early part of the present century, some have since 

 been recognized as being only the two sexes of the same specific 

 type. Kingsley, G. 0. Sars, &c. have shown that Hippolyte borcalis^ 

 Kr., is the male of H. polaris. Sab., and that H. PliippsH, Kr., is 

 the male of H. turyida, Kr. Now if we run over the lists of the 

 habitat of Phryxus abdomiaalis and Gyye hippolytes, we find with 

 surprise that these parasites have constantly been indicated up'-'h 

 Hippolyte polaris and H. taryida, never on the male forms H. 

 horealis and H. Phippsii. In a recent and very careful work upon 

 the Crustacea of the west coast of Greenland, H. J. Hansen, after 

 having indicated the presence of Pliryxus abdominalis upon Pan- 

 dalus Montagui and four difterent species of Hippolyte, adds that of 

 the comparatively large number of individuals of this Bopyrian 

 observed by him not one was attached to a male host. Lastly, 

 there is a curious fact to be noted. Kroyer, whose works are 

 generally so precise and exact, says, in his monograph of the genus 

 Hippolyte, that the female genital aperture is situated in these 

 Carides at the same point as that of the males, that is to say, at the 

 base of the coxae of the posterior feet. Is it not probable that 

 Kroyer made this erroneous observation upon infested males which 

 he took for females ? This is a point to which I would call the 

 attention of the Scandinavian zoologists. There are interesting 

 investigations to be pursued upon a series of phenomena which are 

 still very little known. — Comptes Eendus, February 13, 1888, 

 p. 502. 



