3528 Dublin Natural History Society. 



tance, to drop it as though of no use ; and it invariably happened, that if another fish 

 took up, by any chance, a straw which had been thus rejected, he also, after a short 

 while dropped it, as if his instinct informed him that it was worthless. The time the 

 nest takes in building varies considerably ; one that I timed took five hours in the 

 building, from the time the first layer of straws was laid till the fish stopped work. I 

 never was fortunate enough to see the operation of depositing the spawn, as I never 

 was able to spend more than five or six hours at a time watching the fish, and believe 

 the spawn is deposited in the dusk of the evening. The spawn having been deposited, 

 the male, or, as the country people call him, the cock, mounts guard, never going far 

 from the nest, at least for a time, and may be seen hovering over the sacred deposit, 

 ready to give battle to any enemy approaching its neighbourhood. At this time they 

 are very bold and pugnacious, and I have known them even to dart at my hand and 

 strike me with their spines when I went to take the nest. How long this watch is kept 

 up I am not positive, but I think it must be continued till their young are hatched, as 

 I never found a nest unguarded. These are the principal observations I have been 

 able to make on this little fish. I doubt not that they have occurred to other natural- 

 ists; but as I do not find them recorded, I feel my self justified in bringing them before 

 your Society. 



" As to the distribution of this fish, it is found through the entire course of the ri- 

 ver, from its head in the Butt of Kippure to the Liffey mouth, and in all its tributaries. 



" Of other fishes there are twelve, three of which at least, if not five, were intro- 

 duced. They are : — 



" 1. The trout (Salmo Fario), also found throughout the entire length of this river 

 and its tributaries. In the upper part of the stream, near its source, they run very 

 small, seldom if ever exceeding from a quarter to half a pound in weight; in the lower 

 parts of the stream they have been caught weighing as much as 10 fbs. ; the general 

 weight, however, here seldom exceeds 3 tt>s. The year before last I saw one taken on 

 an eel-line, which wanted but an ounce of 4 Ifos. 



" 2. The salmon (Salmo Salar) principally come up the river during the winter and 

 spring floods ; salmon fry are, however, taken nearly every autumn. 



" 3. The gravelling (Salmo Salmulus), principally found in the lower part of the 

 stream, and swarms in the river at particular seasons. 



"4. The loach (Cobitis barbalula), found plentifully all through the river. The 

 largest I have seen were taken a little below the fair-green at Donnybrook ; they ex- 

 ceeded 6 inches in length. 



" 5. The flounder, (Platessa Flesus). This fish formerly, before the erection of 

 Haigh's weir, used to be quite common all along the fair-green. The erection of this 

 weir confined them to the portion of the river below it, so that the only specimen I 

 know of as having been taken in Donnybrook, was a small one, about the size of a 

 crown piece, taken by teeming a hole after a flood, just below where the wooden bridge 

 used to stand to within the last year. The weir to which I allude has been removed, 

 and flounders are now taken up as far as Ball's-bridge. 



"6 and 7. Both the sharp-nosed and blunt-nosed eels (Anguilla acu tiros tr is and A. 

 laiirostris) may be taken at any time, but especially after the early autumnal floods ; 

 they grow as large as from 2\ tbs. to 3 tbs. weight. 



u 8. The rudd (Leuciscus erythrophthalmus). These used to be very common in the 

 lower parts of the stream below Ilathfarnham, but a few years since, owing to the dele- 

 terious effects of the waste waters from some mills, they became very scarce ; they are, 



