IT 



ON A PEOBABLY NEW SPECIES OF LAMPEET 

 FOUND IN TASMANIA.- 



By E. Swaebreck Hall, Fellow of tbe Eoyal Society of 

 Tasmania, &c., &c., &c. 



The singular fish I have the honor to lay before this monthly 

 meeting of the Society, was transmitted to me by the Eev. E. 

 C. Marum, of Jerusalem, with the request that I would, 

 present it to the Museum, if worthy of acceptance. It was 

 caught by Mr. John Ibbott, near Stockdale, six miles south of 

 Jerusalem, whilst netting for rock-roach, in the Coal Eiver. 

 This part of the river is entirely fresh water, and far above 

 tidal influence. When removed from the net it was living, 

 and firmly adhering by its sucker-like mouth to a rock-roach 

 fish. "When placed in a dish of water," says the Eev. Mr. 

 Marum, " he at once adjusted his pouch charmingly, remind- 

 ing me of the days when I used a set of bladders in learning 

 to swim ; he seemed to sink and rise then as a boat or ship 

 does when at anchor as the waves or ripples move them." 



I submitted this fish to the inspection of the members 

 present at the last meeting of the Physical Section of the 

 Society, and it was thought advisable to refer its further 

 examination, and the discussion of its peculiarities, to this 

 monthly meeting of all the Fellows. 



In comparing it with one of the specimens of a marine- 

 lamprey caught in the Tasmanian seas, it is apparent that, 

 in comparison to length, it is much thicker and has a larger 

 head. The special distinctions, however, are the large pouch 

 it has beneath the gill openings, and the two ridges on its 

 back, near the caudal extremity. In U'one of the descriptions 

 of lampreys, either fresh- water or marine, that I have read is 

 there any account of the singular and very capacious bag 

 beneath the gill openings that I have alluded ta. The Eev.. 

 Mr. Marum would seem to infer that it is of the nature of an 

 air-bladder or float, but if so it is of very unusual thickness. 

 At first we were inclined to consider this curious appendage 

 as an abnormal growth, and not a natural portion of the Coal 

 Eiver lamprey. But I find that all caught there have been 

 similarly characterised. One was caught last week, several 

 at different times before in the previous five years. I have 

 deferred opening this pouch and examining its anatomical 

 structures until this meeting. As far as my scanty knowledge 

 of the natural history of fishes enables me to judge, I believe 



