THE STICKLEBACK FAMILY. 225 



Perhaps the fresh-water sticklebacks and their life-history 

 are more generally known than their cousins of the seashore : 

 their little nests, carefully and jealously guarded, the pugnacious 

 instincts of the males and their bright colours, are themes 

 which have been dwelt upon by naturalists from time to time. 

 The fifteen-spined, or marine species, whilst resembling its 

 fresh-water allies in its curious nest-building propensities, does 

 not develop any bright colours during the breeding-season, so 

 that the sexes cannot be distinguished from one another by 

 their hues ; both are clothed in a sombre brown harmonising 

 with their surroundings. The building of the nests or nidifica- 

 tion, and the early stages of development have been followed in 

 considerable detail by Prof. Prince at St Andrews Laboratory 

 and the following account is mainly taken from his publication 

 upon the subject 1 . 



The nests are to be found during May and June in 

 sheltered rock-pools between tide-marks and often in the 

 higher pools, and they consist mainly of the sea-weeds which 

 are found in great profusion in such localities. Couch records 

 the occurrence of a nest in the loosened strands of a rope, 

 suspended in the water. The appearance of a completed nest 

 may be seen in the Frontispiece to this work, and it will be 

 readily noticed that in this particular instance a small plant of 

 Fucus has formed the basis of the structure ; this example 

 measured from 8 to 10 inches in length and 5 to 6 inches 

 in its widest diameter, and is now in the University Museum of 

 St Andrews. To the Fucus are added small fragments of Ulva, 

 Corallina and even Hydrozoa (Zoophytes) and the whole are 

 firmly woven together by a glutinous iridescent thread-like 

 material which is secreted and manipulated by the male. Upon 

 completion of the nest the female deposits the eggs within the 

 various cavities and interstices between its component materials, 

 and the whole is then complete. The cavities are partly formed 

 in the process of building and partly produced after completion 

 of the structure by the help of the snout or even of the whole 

 body ; the parent-fish may often be observed passing through 

 and through the nest, enlarging the cavities to suit its fancy. 



1 Ann. Nat. Hint. Dec. 1885, p. 487. 

 M. F. 15 



