Miscellaneous. 375 



of a much lighter colour, and whiter beneath than the generality 

 of the specimens ; but this may arise from the animal having been 

 exposed to the light. 



Mustela xanthogenys from California. 



These animals are known from the black-faced weasel (M. brasili- 

 ensis) by their pale brown colour, with the head of the same colour 

 or only darker brown. 



The first specimen described had only two small white spots on the 

 forehead between the eyes, and some white hairs in front of the ears ; 

 but in a specimen lately received the head is darker brown, with a 

 large square pale spot on the forehead between the eyes, a broad 

 white spot on the upper lip under the eyes, and an oblique white 

 streak on the side of the head at the back of the eyes and extending 

 in front of the ears. The throat and the underside of the body, a 

 bright reddish yellow. The tail is short ; but this may depend on 

 the manner in which it was skinned. 



Mustela affinis. 



There is in the British Museum a large specimen of a weasel from 

 New Granada, of a dark brown colour and rather darker head, which 

 has a white streak on the side of the head in front of the ears, but 

 no white mark on the forehead. It is most probably a distinct 

 species ; but its characters want confirmation. 



It has been regarded as a large specimen of M. aureoventris, but 

 is very different from it. It may be a variety of M. brasiliensis. 



On the Encystation of Bucephalus Ilaimeanus. By M. A. Giard. 



Von Baer long ago (1826) noticed a singular parasite of Anodonta, 

 which he named Bucephalus polymorphus. This parasite was sub- 

 sequently better investigated by Steenstrup and Von Siebold, who 

 assigned it to its true place in the system. 



In 1854 M. de Lacaze-Duthiers made known another species of 

 the same genus, Bucephalus Ilaimeanus, which he obtained in the 

 Mediterranean, and which lives as a parasite in the genital glands 

 of the oyster (Ostrea edulis) and cockle {Cardium rust i cum), causing 

 them to be sterile. The sporocysts and the cercarian form of this 

 Trematode were carefully figured in a fine memoir published in the 

 ' Annales des Sciences Naturelles.' 



Claparede has since found this curious Trematode at Saint Vaast- 

 la-Hougue, on the coast of Normandy*. It was by fishing in the 

 open sea with the towing-net that he procured the Bucephalus pretty 

 frequently. The individuals figured by Claparede differ a little 

 from those represented by M. de Lacaze-Duthiers ; but this differ- 

 ence, which relates principally to the form of the lamellar appendages, 



* Beobachtungen iiber Anatomie &c. an der Kiiste von Normandie, 

 1863. 



