JAPANESE SIXGLETHORN. Monoce.ntris Japonicus. 



Fifteen- spined Stickleback, made in the end of an old rope : " A singular instance of 

 constructive skill and patience in the formation of its nest, which occurred within my 

 knowledge, is deserving of remembrance. The situation selected was the loose end of 

 a rope, from which the separated strands hung out about a yard from the surface, over 

 a depth of four or live fathoms, and to which the materials could only have been brought, 

 of course, in the mouth of the fish, from the distance of about thirty feet. 



They were formed of the usual aggregation of the finer sorts of green and red seaweed, 

 but they were so matted together in the hollow formed by the untwisted strands of the 

 rope, that the mass constituted an oblong ball of nearly the size of the fist, in which had 

 been deposited the scattered assemblages of spawn, and which was bound into shape with 

 the thread of animal substance already described, and which was passed through and 

 through in various directions, while the rope itself formed an outside covering tc 

 the whole. 



We can scarcely suppose that such A nest can have been the work of more than a couple 

 of fishes, but the grains of spawn had grown to almost the size of radish -seeds, and in 

 collective bulk seemed greatly disproportionate to the size of the parent, and only to be 

 explained by the well-known fact, that the ova of fishes generally obtains an increase of 

 bulk by the absorption of water after exclusion ; which fluid may be supposed to exert 

 considerable influence on the further development of the young. The embryo of this fish, 

 as is believed to be the case with many others, is not found to bear a close resemblance to 

 the parent, and in fact may be said to pass through a decided metamorphosis in the course* 

 of its final development." 



The jaws of this species are much elongated, and the under jaw protrudes well beyond 

 the upper. Along the back runs a row of fifteen spines, short, sharp, slightly hooked 

 backwards, and each with a very slight membrane. Along the lateral line runs a series of 

 keeled scales, and on the abdomen are two bony plates, bearing on their inner edges two 

 sharp spines of unequal length. If the body be severed at the centre, the line of section 

 will be nearly a pentagon. The upper part of the head, body, and tail is olive-green, taking 

 a golden tint on the sides. The rest of the body is silvery white. The length of this fish 

 varies from five to seven inches. 



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