On the Trematode Parasites of British Birds. 245 



by M. Clievreux is an attribute of the changed environment. 

 I do not know whether a similar colour characterizes those of 

 other open waters. As to the origin of Bathyonyx, however, 

 we have so far no indication of its derivation from subter- 

 ranean ancestors ; and it appears probable, according to 

 Prof. Vejdovsky, whose judgment is based upon its general 

 characteristics and the details of its organization, that its 

 progenitors lived in the open waters of Lough Mask and that 

 its present characters are the result of its existence in the 

 lowest depths. My latest researches have also strengthened 

 the probability of his suggestion that a habit of burrowing in 

 mud may have enabled Bathyonyx to escape capture by the 

 dredge, which skims the surface o£ the lake-floor. Never- 

 theless a considerable amount of mud was subjected to exami- 

 nation on each occasion, which produced nothing but some 

 N. Kochianus. 



The latter portion of Prof. Vejdovsky's paper on the 

 synonymy of 



Gammarus Caspary, Pratz, 

 Gammarus Kochianus, de Kougemont, 

 Niphargus Kochianus, Vejdovsky, 

 Niphargus Caspary^ Wrzesniowski, 

 Niphargus Kochianus, Chilton, 



has been omitted. — Wm. F. de Vismes Kane.] 



XXXVIIL — Observations on the Trematode Parasites of 

 British Birds. By William Nicoll, M.A., B.Sc, Gatty 

 Marine Laboratory, St. Andrews. 



Towards the end of last spring I had an opportunity of 

 examining several of the commoner species of shore-birds. 

 These were, unfortunately, in most cases not in the best 

 condition for helmiuthological investigation, as I seldom 

 received them till at least a day after they were killed, when 

 the parasites were almost always dead. The immediate 

 application of weak formalin, however, preserved their 

 anatomical details rather well, although it rendered them 

 unfit for histological work. For this reason important 

 features in some cases are only superficially described, a 

 matter which I hope to improve shortly with the lielp of 

 better material. These observations are thus to be regarded, 

 to a certain extent at least, as merely preliminary. 



