158 DR. H. LYSTER JAMESON ON THE [Mar. 4, 



and rediscovered by me in the Scoter, CEdemia nigra L., from 

 Bridlington Bay and the Yillaine Estuary. 



After finding the Sporocyst I made a careful examination of 

 such fishes and gulls as I could secure at Billiers, but could find 

 no parasite corresponding to the larva. However, on enquiring 

 of the fishermen I was informed that the great enemy of the 

 mussel in those waters is a diving dvick, locally called " Cane 

 mouli^re," which frequents the Villaine in winter. M. d'Hamon- 

 ville, to whom I wrote on the matter, had no hesitation in saying 

 that this bird was CEdemia nigra. On my visit to Billiers in 

 December last I proved, by shooting an example and procuring 

 fovu- others that were taken in nets, that it was so. The name 

 " Cane mouli^re " seems to be applied to another duck as well, 

 probably the Scaup, Fuligtda marila Linn. A few young Scoters 

 remain on the Yillaine during the summer months. 



The Scoter is very common in winter at the mouth of the 

 Barrow Channel, just opposite the pearl-bearing mussel-beds. 



Before going to Billiers in December I had proved the occur- 

 rence of L. somaterice (Levinsen), associated with Levinsenia 

 pygmcei(,m Lev., in a specimen of CEdemia nigra sent me from 

 Bridlington by Mr. G. Williamson. 



The Scoter received from Bridlington was in a rather advanced 

 state, and I could only determine the presence of a few examples 

 of L. somaterice in the hinder part of the small intestine. But 

 the five specimens procured on the Yillaine Avere infested with 

 L. somaterice from the stomach to the anus and even in the caeca. 

 I calculated that each specimen contained at least six thousand 

 examples of the parasite. Levinsenia pygmcetmi Linn., which 

 occurred abundantly in the Bridlington specimen, was not found 

 at Billiers. The intestine of the Bridlington duck contained 

 nothing but fragments of Mytilus-&\\e\[^. The example which I 

 shot at Billiers was feeding over mussel-beds, and the other four 

 were caught in special nets which are placed on the beds of 

 mussels at ebb tide, and in which the birds get entangled when 

 they visit these beds with the flood, to feed. 



These Billiers specimens had apparently been feeding exclu- 

 sively on mussels, as no other food was found in them, except that 

 one individual contained about half a dozen Nucula sp. and a 

 broken i^Yi?or^?^a-shell, in addition to Mytilus. In the crop and 

 stomach some of the mvissels were still entire, and specimens up 

 to 40 millim. in length were found ; in the stomach the shells are 

 crushed, and pass through the intestine in small fragments at most 

 a few millimetres in diameter. 



The striking likeness, except for the matter of size, between 

 the Mytilus-worm. and Zeucithodendrium somaterice, and the 

 occurrence of the latter in the two birds that are known to feed 

 par excellence on mussels, is almost sufficient to prove their 

 identity without the feeding experiment. I hope, however, to 

 make this experiment if birds can be secured. So far I have been 

 unable to purchase live examples, although I have made enquiries 



