376 Miscellaneous. 



did not seem to the Gcnevese naturalist of sufficient importance to 

 necessitate the establishment of a new species. Notwithstanding 

 his energetic researches, Claparede was no more successful than his 

 predecessor in ascertaining the ulterior destiny of the Cercaria 

 Haimeana. 



Bucephalus Haimeanus also occurs at Etaples and in the neigh- 

 bourhood of Boulogne-sur-Mer. Guided by certain theoretical 

 notions, the result of investigations of the parasitic Crustacea, I 

 have been more fortunate than my talented predecessors, and I have 

 been able to ascertain the encystation of the Bucephalus. 



My observation was made upon the garfish (Belone vulgaris, Val.). 

 This fish (called the maquereau cVete at Boidogne, and becassine de 

 mer at Abbeville) comes commonly into the market at Boulogne 

 during the months of May and June and the beginning of July. 

 The viscera of the fish, especially the liver, the genital glands, and 

 the peritoneum, are frequently filled with little cysts, affecting a 

 cylindrical form, terminated at one extremity by a ball slightly 

 drawn out into a point, like a thermometer in course of construction. 

 By tearing carefully a certain number of these cysts, the Bucephalus, 

 not yet transformed, will be found in some of them. 



My anatomical researches, interrupted in the month of July, 

 could not be carried so far as I wished. However, I must say that, 

 like Claparede, it is impossible for me to accept the opinion of M. 

 de Lacaze-Duthiers, when he says of the Bucephalus, " we observe 

 in it a general cavity which may be regarded as a digestive cavity." 

 The arrangement of the apertures and their physiological offices 

 also appear to me to require being studied afresh. 



What does the encysted Bucephalus become ? Does it arrive at 

 maturity in the body of the garfish, or does it undergo a new mi- 

 gration ? In the latter case, which seems most probable, is this 

 migration active or purely passive ? This is what we have to discover. 

 Claparede several times found the Cercaria Haimeana attached to 

 Sarsice or Oceania? ; on one occasion the Cercaria had lost its two 

 long appendages, but it was still destitute of reproductive organs. 

 From this Claparede concludes that this fact was accidental, and 

 that the Medusae are only momentary hosts for the Bucephalus. 

 I have myself met with an adult Trematode in the ccelenteric cavity 

 of Cydippe pileus, which, in the spring, is sometimes thrown up in 

 abundance on the beach at "Wimereux ; but there is nothing to lead 

 me to suppose that there exists any genetic connexion between 

 this Trematode and Bucephalus Haimeanus. 



According to Von Siebold, Bucephalus polymorphic is converted 

 into Gasterostomum jvmbriatum in the digestive tube of Percajluvia- 

 tilis and P. lucioperca ; it is also found encysted in Cyprini. It 

 seems therefore more probable to suppose that the Bucephalus 

 Haimeanus encysted in Belone vulgaris becomes metamorphosed 

 into a species of the genus Gasterostomum in the intestine of some 

 large fish to which the garfish serves as food. Lacepede informs 

 us, in fact, that when the garfish emits the deep water to go and 

 spawn near the shores, it becomes the prey of the sharks and dog- 



