SALT-MARSHES OF NOETHUMBERLAND AND DURHAM. 121 



Wear, Jarrow Slake, Seaton Sluice, the mouths of the Wans- 

 beck, Coquet and Aln, as well as Burgh Marsh on the Solway : 

 besides these I have received some scanty gatherings from the 

 Blyth and Tweed ; and the Eev. A. M. Norman and Mr. David 

 Robertson have kindly supplied me with notes of species taken 

 in similar situations in Scotland and the Channel Islands. 



My attention has been chiefly confined to the Crustacean Fauna, 

 and it is that alone which I have examined minutely, though, for 

 the sake of more general interest, I have always noted such other 

 animals as presented themselves to my attention. 



There seems to be very little variety amongst the Mollusca in- 

 habiting these marshes. Rissoa uIvcb is the only gasteropod (ex- 

 cepting Nudibranchs) which I have found alive in strictly brack- 

 ish water, where it occurs often in _reat abundance ; but pools 

 further removed from the saline influence, and above the highest 

 limit of spring tides, where, to the taste, the water is quite fresh, 

 are frequently inhabited by a peculiar mixed Crustacean Fauna, 

 seeming to indicate some slightly saline character. In such situ- 

 ations we meet with Limnea 'peregra and Pisidium imlchellimi, 

 which are quite fresh-water species. The only marsh in which 

 I have taken any Nudibranchiate species is Hylton Dene, where 

 Alderia viodesta occurred in great abundance, in company with a 

 smaller species, Limapontia depressa, which was first found there 

 by Mr. Albany Hancock. These two species have also been 

 found in company at Loughor Marsh, near Swansea, by Mr. C. 

 Spence Bate and Mr. Muggridge. In the " debateable ground," 

 between fresh and brackish water, I have also met with the 

 beautiful polyzoon Phmiatella rep)ens ; but in this case the ge- 

 neral vegetation and animal life of the pool was decidedly that 

 of fresh water, differing only in the presence of several species 

 of stalk-eyed Crustacea, which usually inhabit brackish water.* 

 For further particulars of this interesting locality I must refer 

 the reader to my paper on the Zoology of Hylton Dene. 



The higher orders of Crustacea are almost always repre- 

 sented in salt-marsh pools by Carcinus vianas, Palmiwn varians, 



* Paliemon varians, Myni.', vulgaris, ami Corophium fongiconie occur in such n situation In 

 Hylton Dene. 



