CLASS PISCES. 97 



up our rivers, as far as the limits of salt water, and perhaps 

 even beyond it. It is most wary, and difficult to keep in the 

 net when enclosed. It jumps over the head-rope, and some- 

 times makes a grand rush with its companions in a body, 

 tearing its way out, unless the net is in good order. If one 

 succeeds in leaping over the head-rope, the whole shoal follows 

 like a flock of sheep. 



Mugil chelo, Cuv. LESSER GREY MULLET. 



This is not as common as the last-mentioned species. 

 Some specimens were, however, taken, in June, 1895, in the 

 Blackwater Estuary. 



Family GASTEROSTEID^E, Day. 

 Genus GASTEROSTEUS, Artedi. 

 Gasterosteus aculeatus, Linn. THREE-SPINED STICKLEBACK. 



From its habits and frequency, this is one of the most in- 

 teresting of the family. It occurs in all situations, in streams, 

 ponds, and (I had almost written) puddles. It is also to be 

 found in pools where fresh and salt water are commingled. 

 I have found this a most variable species, both in size and 

 armature. In some ponds all the individuals are all similar, 

 whilst in other ponds or streams various forms occur. I have 

 never observed which of the named varieties are the most 

 common. The Three-spined Stickleback is a veritable tyrant 

 of the water, and appears to fear few enemies, although he is 

 so small. 



Gasterosteus pungitius, Linn. TEN-SPINED STICKLEBACK. 



TINKER. 



This is not nearly so common as the last species, being 

 found more frequently in small streams rather than ponds, 

 although it occasionally occurs in the latter situations. I 



have never found it in brackish water. It is equally pugna- 



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