On Bucephalus polymorjohus. By H. J. Slaeh. 145 
M. Lacaze-Dathiers exclaims, What idea can we form of the 
sporocysts ? It seems natural to regard them as the mothers of 
the numerous brood they contain. Their whole body is trans- 
formed into a veritable matrix, or chamber of incubation. But 
these mothers, born fecund, do not arrive at a form which 
terminates or begins a series of changes : they are themselves 
larvae. According to the observations of Siebold, they are only a 
part of an embryon; and Steenstrup noticed in mussels larvae 
resembling parameciae, which after losing their ciHated epithe- 
lium transformed themselves into a germinative tube. This, then, 
is another form to add to those already so numerous of this same 
helminth." 
M. Lacaze-Duthiers found these sporocysts subject to lively 
contractions, while those of B. polymorphus described by Von 
Baer were rigid. "Another remarkable fact is their budding 
.... when a bud is only slightly protuberant it contains nothing 
but a little brown granular matter." He adds that " the oysters 
of Mahon, and the cockles of the Lake of Thun, near Cette, 
were found to be sterile, these helminths occupying the conduits 
of the genital glands, and even of the intertubular spaces." Fig. 6 
represents the sporocyst, copied from Lacaze-Duthiers, and Fig. 7 
the complete animal. 
Further light is thrown upon B. Haimeanus by a note of 
M. Alf. Giard in 'Comptes Kendus,' Aug. 17, 1874. He mentions 
its discovery by Claparede* on the coast of Normandy, fishing with 
fine nets. His specimens differed a little from those of Lacaze- 
Duthiers, chiefly in the form of the lamellar appendages, but not 
sufficiently so to require the formation of a new species. M. 
Giard found it encysted in the liver, genital glands, and other 
organs of the garfish {Belone vulgaris). His anatomical inves- 
tigations were not completed, but he agrees with Claparede in 
rejecting the opinion of Lacaze-Duthiers, that the general cavity is 
a digestive one. He inquires, " What becomes of the encysted 
Bucephalus ? Does it reach maturity in the body of the garfish, 
or undertake a fresh migration? and is that migration active 
or passive? This remains to be discovered." He states that 
Claparede found the Cercaria Haimeana several times fixed on 
Sarsia and Oceania, and he himself found an adult trematode in the 
intestinal cavity of Cydippe pileus, but with Claparede he regards 
such appearances as accidental. According to Siebold, B. poly- 
morphus transforms itself into Gasterostomum fimhriatum in the 
digestive tube of the perch (Perca fluviatilis, Lucio-perca), and it 
is also found encysted in the carp. "It is therefore reasonable 
* Claparede, Beobachtungen iiber Anatomie, &c., an der Kuste von Nor- 
mandie, 1863. 
