THE POLLAN. 171 



herrings, were got in Lough Derg [a mere expansion of the river Sliannon] very 

 near this, about 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. cbipeoides of Nilsson.f 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 Zoographia 

 renders it doubtful whether they be the same fish. Between it and Nilsson's C. 

 clupeoides I perceive no specific (though a considerable individual) ditt'erence, 

 and consider them identical, if the phrase " tereti-compresso," applied to the 

 body in his specific characters, be taken singly, and be translated, roundly com- 

 pressed ; but if " tenue," J applied again to the body in the detailed descrip- 

 tion, mean that it is thin or compressed, the species cannot be the same, the in- 

 dividual under consideration being very thick for one of the Coregoni. 



Nilsson is altogether silent on the history of this species, stating merely that 

 it was sent him with other iishes from Lake Wettern. As this lake communi- 

 cates 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 be- 

 lieved 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 jiresbyter) ; considerable thickness main- 

 tained throughout. § Length 4j inches ; depth where greatest, at origin of 

 dorsal fin, 9 lines, or compared with the entire length as 1 to S^ ; thickness 

 more than half the depth, just behind the head 5 lines, the same at the middle, 

 and \ of an inch before the base of the caudal fin 2 lines ; lateral line for \ of 

 an inch from its origin sloping downwards, thence to its termination straight, 

 and except at the tail, where it is equidistant from each, placed rather nearer 

 the dorsal than the ventral profile ; head 1 1 lines long, or about as 1 to '.i^ in 

 the entire length ; eye large, placed at the distance of its own diameter from the 

 snout, and occupying \ the length of head ; upper jaw truncated, lower round- 

 ish-oval, and when the mouth is closed projecting \ a line beyond the snout (in 

 this respect exceeding that of the vendace, Cor. Wilhighbei, Jard.). The only 

 teeth apparent with the aid of a lens are a few placed regularly on both upper 

 and under jaws, none apparent on the tongue or the vomer ; pre-opercle nearly 

 describing the segment of a circle, opercle from the posterior base gradually 

 narrowing upwards. Fins ; dorsal originating half-way between extremity of 

 lower jaw and base of caudal ; pectorals pointed, nearly ~ the length of head, 

 these and the ventrals of about equal length ; the latter commencing in a Ime 

 with the first quarter of dorsal ; when laid close to the body, the dorsal ap- 

 proaches the tail more nearly than the ventral ; anal distant its own length from 

 the first short ray of caudal ; adipose ending nearly on the same line as the anal. 



D. 15 (1st very short); P. 15;|| V. 1 + H ; A. 16 or 17 ; C. '20i|=Br. 7. 



Scales (judging merely from their impressions, they having been rubbed off) 



* Zoographia Russo-Asiatica, iii. pp. 410, 411. To this work 1 have not had 

 access, but am indebted to my friend Mr. Ogilby for transcribing from it the full 

 description, and sending it me iVom London. 



f Prodromus Ichthyologiaj ScandinaviccP, p. 18. 



X The commencement of the specific characters is " C. corpora elongate, 

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



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

 lateralis of the Fauna Boreali-Amcricana (pi. 89, fig. 1), it might be called 

 " four-sided with the angles rounded off." 



II This number ajjpears in both fins, which are somewhat injured. 



