78 Miscellaneous. 



introduced among the Daeapoda by the Ehizocephalan Clrripedes. 

 While one branch of the Cryptoniscidfe has remained faithful to its 

 first hosts, another has become adapted to direct parasitism upon the 

 Decapods, and has given origin to the group of Phryxus, Bopynis, 

 and the Entoniscidae. 



Thus, by a fact of ethological atavism, would be explained the 

 simultaneous presence, so often ascertained, in the same Decapod, of 

 a Ehizocephalan and a Bopyrian parasite (SaccuUna Oarcini and 

 Portunion Mcenadis, Entoniscus Porcellance and Lernceodiscus Por- 

 cellancB, &c.). 



The existence of a Phryxoid stage in the evolution of the females 

 of most Bopyrinse shows that the genus Phryxus may be regarded 

 as the stock from which there have issued, ou the one hand, the 

 loninse, which are in a manner an exaggeration of it ; and, on the 

 other, the asymmetrical branchial Bopyrinse. This Phryxoid stage 

 is observed in Pleurocrypta^ Bopyrus, Cepon, lone, &c. It has 

 caused many errors on the part of the zoologists who first studied 

 these animals. The Phryxiis-stage of Oepon typus was taken by 

 Duvernoy for the male of that Bopyrian. Phryxus fustieaudatus, 

 Sp. B. & W., is the Phryxus-stage of Pleurocrypta Hyndmanni, Sp. 

 B. & W. * ; Phryxus longibranchiatus , Sp, B. & W., corresponds 

 in part to the Phryxas-stage of Pleurocrypta GalatJu'ce, Hesse {non 

 Sp. B. & W. t). In the Entoniscidas the Phryxus-stage appears 

 less distinctly, and it is possible that this group may have diverged 

 from the stock at a very ancient period, wbidh would be in accord- 

 ance with its more decided parasitism. — Comptes Rendus, May 9, 

 1887, p. 1309. 



On Parasitic Castration in Eupagurus Bernhardus, Linne, and in 

 Gebia stellata, Montagu. By M. A. Giakd. 



In a recent memoir t I made known the curious morphological 

 eff'ects produced in several Decapod Crustacea by the castration pro- 

 duced by the presence of Ehizocephalan or Bopyrid parasites. Fur- 

 ther and very remarkable examples of these phenomena are presented 

 by the hermit-crabs infested by Phryxus Paguri, Eathke, and by 

 the Oehice infested by Oyge branchialis, Corn. & Pane. Although 

 Phryxus Paguri is an absolutely external parasite, the modifications 

 which it occasions are as extensive as those observed in certain 

 Brachyura in consequence of their infestation by Ehizocephalans. 



It is well known what are the external sexual characters of the 

 Eapaguri. In the female the genital aperture is situated upon the 

 basal joint of the third pair of thoracic feet ; in the male this 

 orifice is placed upon the base of the fifth pair of feet, which bears 



* We have met with this Bopyrian of the branchial cavity of Pagurus 

 Bernhardus at RoscofF, and at Equihen, near Boulogne-sur-Mer. 



t We have studied this parasite of Galatkea squamifera at Roscoff and 

 at Fecamp. 



\ Bull. Sci. du Nord, tome xviii. (1887), pp. 1-28. Translated in 

 'Annals/ May 1887, pp. 325-345. 



