DrSLIN KATUBAL HISTORY BOCIETT. 129 



of shark frequently springing several feet out of the water, which the crew 

 pointed out to him as the Thresher shark, from the peculiarity of the action of 

 its tail-fin. 



MAY 9, 1852. 



ON THE SPAWNING OF THB SMOOTH-TAILED STICKLEBACK (aASTXBOSTBUS 

 LEIUBUS), WITH A LIST OF THE FISHES INHABITING THB DODDEE. BT J. B. 

 KINAHAN, A.B. 



Concerning the manner in which this little fish preserves its spawn, not the 

 slightest notice, if I may be allowed to judge from the silence of our latest autho- 

 rities, has been taken by any Enylish naturalist. This is the more strange, when 

 we recollect that a habit, analogous in its nature, has been recorded of another 

 species of the same group, whose habitat (the sea) renders it more difficult to 

 make observations thereon, while the species under consideration mav be found 

 at every man's door, being, without exception, the most extensively distributed 

 of all the British fishes; yet, neither Yarrell in his •♦ British Fishes," nor Sir W. 

 Jardine in the '* Naturalist's Library," makes any mention of this habit, though 

 the latter has recorded the nest- making powers of the marine species to which I 

 alluded just now(G. spinachia). In France, M. Coste has entered very fully into 

 the matter in a paper read before one of the Societies in Paris, in 1847 ; but as the 

 following observations were made long prior to my having seen his paper, and 

 differ in some respects from the facts recorded by him, and as he has not men- 

 tioned the species on which his experiments were made, 1 thought these observa- 

 tions might not be unworthy of a place in your Transactions. In 1846 my atten- 

 tion was first called to this curious habit by a friend of mine. I then made a 

 series of observations, most of which I have been able to confirm during each 

 succeeding year, the substance of which I now hasten to lay before you. Into 

 the question of whether this be a distinct species, or merely a well-marked va^ 

 riety of Gasterosteus aculeatus of Bloch, it is not my intention to enter ; suffice 

 it for us to consider it as a distinct species, the smooth-tailed stickleback, the 

 G. leiurus of Valenciennes and Cuvier. It is the only species I have been able 

 to detect about Dublin, where it abounds in prodigious numbers. When about 

 to spawn, the fish select a suitable spot for the foundation of their nidus, pre- 

 ferring a gravelly bottom, not too deep, and over which a current runs ; hence 

 the best place to look for the nests is where clear streams empty themselves into 

 a river. At such a place you will almost invariably find abundance of them in 

 the months of May, June, and July. Another favourite locality is a large flat 

 stone at the bottom of the river, over the edge of which the water flows, so as to 

 produce a ripple. Having chosen a suitable spot, he (for it is always the male 

 that builds) begins by laying a foundation. This is slightly modified, according 

 to the materials of wliich the superstructure is to be made. If, as is most usually 

 the case of straws and such like, the first thing done is to lay a number of these 

 on the bed of the stream, carefully tucking the ends of them down into the gravel 

 upon which they rest ; across these are laid other straws, the ends of which are 

 either interlaced amongst the first row, or tucked into the gravel. This last 

 operation is always performed by means of the animal's snout, the point of which 

 he places on the end of the straw, &c., and then, raising his body perpendicularly, 

 he thus presses the straw, or other material, among the stones or mud. Amongst 

 and over these straws confervse and such like are interwoven, rendering the 

 whole one compact mass, through which the water, however, can have free pas- 

 sage. He always takes care to preserve a dome-like hollow in the centre, on 

 the top of which there is a small round hole; the edges of this he takes particu- 

 lar care to strengthen, tucking in the straws, and rounding off the edges most 

 industriously ; and every now and then he pauses in his task, and remains hover- 

 ing over the nest, as though trying by the current produced by the motion of his 

 fins whether the structure is secure enough or not. Sometimes the nest is en- 



