Mr. W. Thompson on a new British Fish, 267 



four years ago in the eel-nets, but none since, at least in this 

 quarter." So far only is the history of the species known to 

 me : that the white fish were this Coregonus, I think hardly 

 admits of doubt. 



On examining the specimen, the nearest approximation I 

 find to it is the Salmo clupeoides of Pallas*, and Cor, clupeoides 

 of Nillsonfj who with a query marked Pallas's as synonymous 

 with his species. 



Although there is a tolerable general agreement, yet a want 

 of accordance in some characters between my specimen and 

 the description in the c Zoographia* renders it doubtful whe- 

 ther they be the same fish. Between it and Nillson's C, clu- 

 peoides I perceive no specific (though a considerable indivi- 

 dual) difference, and consider them identical, if the phrase 

 "tereti-compresso," applied to the body in his specific charac- 

 ters, be taken singly, and be translated, roundly compressed ; 

 but if " tenue %" applied again to the body in the detailed de- 

 scription, mean that it is thin or compressed, the species 

 cannot be the same, the individual under consideration being 

 very thick for one of the Coregoni. 



Nillson is altogether silent on the history of this species, 

 stating merely that it was sent him with other fishes from lake 

 Wettern. As this lake communicates with the Baltic, it is to be 

 regretted that we are not informed whether the Coregonus be 

 stationary in it, or migrate to the sea as the Shannon species 

 is believed to do. 



Desc. — General form, gracefully elongated, sloping equally 

 from the centre of back to the head and tail, the anterior and 

 posterior portions of the ventral profile also corresponding to 

 each other, but rather more convex than the dorsal ; rounded 

 in the back (like Atherina Presbyter) ; considerable thickness 

 maintained throughout §. Length 4^ inches; depth where 



* Zoographia Russo-Asiatica, iii. pp. 410, 411. To this work I have not 

 had access, but am indebted to my friend Mr. Ogilby for transcribing from 

 it the full description, and sending it me from London. 



f Prodromus Ichthyologise Scandinavicse, p. 18. 



X The commencement of the specific characters is " C. corpore elongato, 

 tereti-compresso ;" the detailed description " Corpus elongatum, tenue." 



§ It is so formed, especially the anterior half, that like the Coregonus qua- 

 drilateralis of the ' Fauna Boreali-Americana,' (pi. 89. fig. 1.) it might be 

 called "four-sided with the angles rounded off." 



