Trematode Parasites of British Birds. 



in 



fisli, Avliich feed largely ou crustaceans, annelids, and each 

 other. From these and other considerations it would appear 

 that, in the littoral zone, at least, where both have a couiuion 

 feeding-ground, birds derive their Distomid parasites from 

 nioUusks *, while fish obtain theirs from crustaceans, 

 annelids, and each other. This seems to afford an explana- 

 tion of the absence of Distomids in the three above-cited 

 cases. 



For ease of reference I subjoin a list of hosts with 

 their respective parasites : — 



Alca tarda, Linn. Eazorbill. 



Tocotrema liup^ua {Crept.). 

 ? Spelotrenia simile, Jdyersk. (juven.). 

 Lants aryentatus, Briinn. Herriug-GuU. 



Gymnopliallus deliciosus {Olsson). 



Maritrema lepidum, sp. n. 



Parorchis acanthus, Nicoll. 



Spelotrema excellent, sp. n. 



( = Sp. simile, Jdyersk., Nicoll.) 



Tocotrema lingua ( Crept.). 



Monostomum sp. (juven.). 

 Lartis canns, Linn. Common Gull. 



Parorchis acanthus, Nicoll. 

 Lams ridibundus, Linn. Black-headed Gull, 



Maritrema gratiosuni, sp. n. 

 Phalarrocora.r yracidus (Meyer). Shag. 

 ? Cryptocotyle concavum {Crei^l.}. 



Oidemia nigra (Linn.). Scoter. 



Gymnophallus dapsilis, sp. n. 



Psilostomum brevicolle (Crept.). 



Spelotrema pygma3um {Levins.). 

 Oidemia fusca (Linn.). Velvet Scoter. 



Gymnophallus dapsilis, sp. n. 



Psilostomum brevicolle {Crept.). 



Spelotrema pygmfeum {Levins.). 



Monostomum sp. 

 Petidna {Trinyo) atpina (Linn.). Dunlin. 

 Maritrema gratiosum, sp. n, 

 Spelotrema feriatum, sp. n. 



Spelotrema claviforme {Brds.). 



Totanus ealidris, Bechat. Redshank. 

 Maritrema humile, sp. n. 



Intestine. 

 Intestine. 



Gall-bladder. 



Intestine. 



Bursa Fabricii, rectum, 



and intestine. 

 Intestine and caeca. 



Intestine. 

 Intestine. 



Rectum. 



Intestine. 



Intestine, cajca, and 

 rectum. 



Bursa Fabricii. 



Intestine. 

 Intestine. 



Bursa Fabricii (and 



? csecaj. 

 Intestine, Cffica, and 



rectum. 

 Intestine, ca;ca, and 



rectum. 

 Caeca. 



Intestine. 



Intestine, cfcca, and 



rectum. 

 Intestine, crcca, and 



rectum. 



Intestine, 



* An important exception to this is the case of some Spelotrema species, 

 which are obtained, partly at least, from Caiicer payurus and Carcinus 

 jnosnas. 



