168 MALACOPTERYGII. 



ruption of the Avord Graveling, which is generally applied to that fish in the 

 southern counties. 



The Pollan, Coregonus Pollan, Thomp., 



Is the only species of Coregonus yet found in Ireland. It occurs in 

 Loughs Neagh, Erne, and Derg, probably also in Lough Corrib. 



The following notices of the pollan have already been published by 

 me : — 



" In September last (1834) a comparison of the Lough Neagh Coregonus yfiih. 

 the Vendace oi hochmahen (whence I procured specimens through the kindness 

 of Sir William Jardine, Bart.) proved to me that these species are distinct. 

 The disagreement of the former with the Giuyniad or Coregonus of Wales, as 

 described by Pennant, was at the same time very obvious ; and from the exam- 

 ination of an individual of the latter species (lately favoured me by Mr. Yar- 

 rell), and specimens of the Lough Neagh fish, I am fully satisfied that they are 

 specifically different. 



" From the gwyniad, the pollan or Lough Neagh Coregonus differs, — in the 

 snout not being produced ; in the scales of the lateral line ; in having fewer rays 

 in the anal fin, and in its position being rather more distant from the tail ; in the 

 dorsal, anal, and caudal fins being of less dimensions ; and in the third ray of 

 the pectoral fin being longest, the first being of the greatest length in the 

 Gwyniad. 



" From the pollan, the vendace or Lochmaben Coregonus differs so essentially, 

 in its lower jaw being the longer, as well as in its being turned upwards, as to 

 render further comparison unnecessary. 



" The pollan is very uniform in size, its ordinary length being about 10 inches ; 

 none that I have ever seen exceeded 12. The relative length of the head to that 

 of the body is as 1 to about 3| ; the depth of the body equal to the length of the 

 head; the jaws equal, both occasionally furnished with a few delicate teeth; 

 the tongue with many teeth : the lateral line sloping do^^^lwards for a short way 

 from the operculum, and thence passing straight to the tail ; nine rows of scales 

 from the dorsal fin to the lateral line, and the same number thence to the ventral 

 fin ; the row of scales on the back, and that of the lateral line, not reckoned ; 

 the third ray of the pectoral fin the longest. 



D. 2 + 12; P. 16; V. Ill ; A. 2+11; C. 19; B. 9. Vertebrce b<d. 



" Colour to the lateral line dark blue, thence to the belly silvery; dorsal, 

 anal, and caudal fins towards the extremity tinged with black ; pectoral and 

 ventral fins of crystalline transparency, excepting at their* extremities, which are 

 faintly dotted with black. Irides silvery, pupil black. 



" As not one of the Coregoni of which I can find descriptions agrees with the 

 Lough Neagh species, I am induced to consider it as new, and venture to pro- 

 pose for it the name of Coregonus -pollan,* as by this trivial appellation it is in- 

 variably knoAvn in its native district." f 



The above description of the pollan was read before the Zoological Society of 

 London on the 9th of June, 1835. The following particulars 1 then looked for- 

 ward to publish in a paper on the fishes generally that inhabit Lough Neagh, 

 but, until this can appear, the present contribution towards the history of a spe- 

 cies which is certainly distinct from the gwyniad and vendace (the only other, 



* Although the pollan accords not with any Coregonus yet described, it was 

 with much hesitation that I bestowed on it a new name, being fully aware that 

 the same species is often very differently described by different authors, and un- 

 der the impression that it may eventually prove identical with some of the con- 

 tinental Core^roMJ, with which I had not an opportunity of comparing it, — the ac- 

 tual examination of specimens being the only true criterion by which to judge of 

 such closely allied spei^es as this genus presents. 



t Proceedings of the Zoological Society of London for 1835, p. 77. 



