243 On the Pollan of Lough Neagh. 



through the kindness of Sir William Jardine, Bart.) proved to me 

 that these species are distinct. The disagreement of the former with 

 the Gwyniad or Coregonus of Wales, as described by Pennant, was 

 at the same time very obvious ; and from the examination of an in- 

 dividual of the latter species, (lately favoured me by Mr YarrelL) 

 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 la- 

 teral line ; in having fewer rays in the anal fin, and in its posi- 

 tion 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 be- 

 ing 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 downwards 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. Villi. A. 2 + 11. C. 19. B, 9. Vertebra 59. 



" 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, except- 

 ing at their extremities, which are faintly dotted with black. Iri- 

 des 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 propose for it the name of Coregonus pollan* 



* 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 Coregoni, with which I had not the opportunity of comparing it, — the ac- 



