FISHES. 143 



one and a young axolotl. I had given tlie latter its morning 

 worm, which it immediately began to swallow, beginning 

 at one end, when a Bullhead darted from its retreat under 

 a stone, and seized the other end of the worm. This action 

 on the part of the fish commenced a furious struggle between 

 it and the axolotl. As the reptile was the stronger of the 

 two, the fish was literally tossed about in all directions, some- 

 times to the right side of its opponent, sometimes to the left, 

 and sometimes it was turned completely upside down; never- 

 theless, the plucky little fish continued to hold on imtil the 

 worm of contention parted in the middle, and each combatant 

 got a portion of the prey. The fight between the reptile and 

 the fish seemed to last for quite half a minute. 



Miller's Thumbs are said to guard their ova and their little 

 ones, but I have never been able to witness this evidence of 

 parental care on the part of these fish. Perhaps they might 

 be induced to breed in a suitable aquarium, since they so soon 

 become quite tame. 



The Bullhead has a flat and broad head and a wide mouth. 

 The body (seen from above) is very wedge-like in shape. 

 There are two dorsal fibis: the front one is short and some- 

 thing like the front dorsal fin of the perch; the back one 

 is very long, and extends quite close to the base of the 

 caudal fin. The pectoral fins are large and powerful in 

 proportion to the size of the fish. The anal fin is also very 

 long, and is just under the long dorsal fin. The ventral fins 

 are rather small in comparison to the other fins, and upon 

 them the fish often raises itself from the bed of the stream 

 or aquarium. The tail fin is slightly convex. The eyes are 

 rather close together on the top of the head, have golden 

 irides, and are very bright. The colour of the fish varies, 

 but it is generally of a yellowish-brown, blotched and spotted 

 with black. The under-part of the body is nearly white. 

 There is a small spine on each side of the head. 



The Three-spined Stickleback {Gasterosteus aculeatus) (Fig. 

 103), though very beautiful and interesting, ought never to 

 be confined in the same aquarium with any other fish : even 

 in a very large tank it will be a great nuisance. But if it 



