50 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



to spawn. They were never seen in the summer and autumn. 



Specimens of the whole five species were kept alive in the 



aquaria for some weeks. They all spawned at frequent 



intervals, gradually getting smaller each time, and finally 



disappeared. 



A. Scott. 



Nudibranchs from Port Erin, 



Crab pots set off Bradda Head and brought ashore at 

 the end of the season, October 1st and 2nd, yielded a rich 

 harvest of invertebrates, including a large number of Nudi- 

 branchs belonging to at least a dozen species, the more notable 

 of which were : — Triopa clavigera, Polycera quadrilineata, 

 Ancula cristata, Doto coronata, Coryphella landsburgii, Galvina 

 picta, Galvina farrani, Tergipes despectus, Facelina drummondi, 



and the rare Hero for mosa. 



E. C. Herdman. 



(6) The Oyster Parasite, Bucephalus haimeanus. 



While examining the morphology of cockles, during a 

 vacation class for school teachers, held at Piel, Barrow-in- 

 Furness, in August, 1920, several molluscs were noticed in 

 which the tissues in the dorsal region of the visceral mass were 

 stained yellow. On further examination it was seen that this 

 colouration was due to a tangled mass of very long, filamentous 

 sporocysts of a trematpde parasite. These contained very 

 numerous cercaria larvae. The most prominent character of 

 the latter was the extremely long, highly mobile, bifurcated 

 tail. A further collection of cockles was made and examined. 

 It was very easy to distinguish the infected molluscs by the 

 faint yellow staining of the tissues round the liver and gonads. 

 About half-a-dozen individuals in fifty were thus found to 

 harbour the parasites which are provisionally identified as 

 above, 



Jas. Johnstone. 



