SEA-FISHERIES LABORATORY. 287 



bouring families, but having some affinities with the 

 Sealibregmidre, Opheliiche and Maldanida3. 



Parasites. 



I. — A considerable number of specimens of Arenicola, 

 from the Lancashire coast near Blackpool, were found to 

 contain small ovoid bodies attached to, or imbedded in, 

 the muscles of the anterior region. These proved to be 

 Distomid cercarige which had migrated into this position 

 and encysted there. Each is about half a millimetre 

 long and a third of a millimetre broad and is surrounded 

 by a moderately thick cyst-wall. In each specimen the 

 two suckers, the muscular pharynx, the two limbs of the 

 intestine, about a dozen flame cells and the rudiments of 

 two of the reproductive organs (testes ?) may be distin- 

 guished. These would remain encysted in Arenicola 

 until the worm was eaten by the final host (probably a 

 fish or a bird), in which the cercaria would be liberated 

 from the cyst and would grow into a " fluke." 



II. — In other specimens Coccidia are occasionally 

 very abundant in the walls of the stomach, intestine and 

 nephridia. They are much more common in A. grubii 

 than in A. marina. They are spherical or ovoid cells, 

 each about OT-f mm. in diameter when fully grown, with 

 a vesicular nucleus containing a large nucleolus. A few 

 cysts, 0'2 to 0*25 in diameter, each containing a few 

 thousands of rounded spores (sporozoites) have been met 

 with on the outer surface of the gut or attached to the 

 muscles of the body wall. Each spore is 3 to 4// in 

 diameter, and consists of a thin covering of protoplasm 

 enclosing a (comparatively) large nucleus. 



As the lugworm is a common food of fishes (especially 

 of flat fish), a knowledge of its parasites is desirable, as 



