LARVAL TREMATODES OF THE NORTHUMBERLAND COAST. 45 1 



In the following table measurements are given of the two 

 worms, which agree fairly well. 



Oral sucker 

 Length of pharynx 

 Breadth ,, 



Ventral sucker ... 



Egg 



Testis 



DistomiiDi Icptosomum, 

 Villot. 



From Dunhn. 



0'056 mm. 



0*064 inm. 



0*024 mm. 



0"200 mm. 

 O'oSo X 0*050 mm. 

 0*400 X 0*200 mm. 



Distu)iium 

 ( Ech inostoinum). 



From Turnstone. 



0'c6 mm. 



0"o6 mm. 



0*049 111™. 



0*26 mm. 

 o*o8o X 0*052 mm. 

 o*6o X 0*26 mm. 



Bucephalus haimeanus, Lacaze-Duthiers (see Plate XIII.). 

 This peculiar cercaria has long been known, but it appears 

 few have found it in Britain, the only record I know being in 

 the Report of the Lancashire Sea Fisheries Scientific Investi- 

 gations for 1904, " Internal Parasites and Diseased Condition 

 of Fishes," by James Johnstone, B.Sc. In this paper a Buce- 

 phalus larva from Cardmm ednle, " probably B. hawieamis" is 

 mentioned (p. 106-7). It is satisfactory to be able to record 

 it for Northumberland, although only one specimen of the 

 cockle Cardium edule infested with the parasite was found. 

 This was from the Mussel Scaup, Holy Island, which forms 

 part of Fenham Flats, and as the oysters kept by Lord 

 Tankerville are planted there, it is very probable that the 

 cockle was infected by reason of its proximity to these. This 

 worm is a well known parasite of the oyster, and Lacaze- 

 Duthiers* describes it from that mollusk as well as from 

 Cardium rtistictim, a cockle closely resembling C. edule, but 

 larger. Huetf also found it in C. edule. A full and detailed 

 account of its life history in America has been published by 

 Mr. David Hilt Tennantif. The author in this work shows 

 that Bucephalus haimeanus is the larval form of Gasterostomum 

 gracilescens (Rnd.), inhabiting the intestine of the Angler 



* Ann. des Sci. Nat., S&*. VI., Tom. I., 1854. 



t BulL Soc. Linn, de Normandie II., 1889, p. 145-9. 



X Quarterly Journal of Microscopical Science, N.S., No. 196 (Vol. 49, Part IV.), 

 Feb., 1906. 



