34 



Part III. — Twenty-seventh Annual Report 



walls of the honeycomb seemed to be broadening, and in this way the 

 cavity was reduced in size. 



The developing testis is pink. 



Winter Spawner. — The herrings included under this denomination 

 include doubtless both those that are preparing to spawn for the first 

 time, and also winter spents. 



Summer Sjjawner. — The developing testis shows the honeycomb structure, 

 if a portion of it is teazed out and washed in water. In a full testis the 

 honeycomb network is composed of extremely delicate strands. The outer 

 skin of the large testis is also extremely thin. The tissue of a small testis 

 may be comparatively tough. 



There is difficulty in determining whether to designate late summer 

 spawning herrings as actually belonging to the Summer Spawning group. 

 Similai'ly in this month many of what are regarded as winter spawning 

 iierrings are so far advanced that they must almost of necessity' spawn 

 before winter, that is to say, in autumn. 



An interesting comparison may be made between the herrings from the 

 Clyde and those obtained on the East Coast. The comparison is made by 

 means of the female specimens. They are contrasted according to the 

 condition of development as shovvn in the size of the ova in the various 

 individuals. The herrings are arranged in the following table, the 

 number at each size being given : — 



Comparison between the Herrings of the Clyde and East Coast in respect to the 

 Development of 1;he Ovary as shown bj^ the Diameter of the Ova, in mm. 



It is seen that the East Coast specimens are distinctly ahead of those 

 from the Clyde in the development of the ovary. The range of the sizes 

 of the eggs is in the former from -l-l-O mm., while that for the Clyde is 

 from •05-'8 mm., with one female carrying eggs 1*2 mm. in diameter. In 

 the development of the ovary the two lots of herrings overlap. In each 

 there is a mixture of winter and summer spawners, but so far as the 

 material goes there is no sharp division between the winter and summer 

 spawning herrings. There is no indication of any natural division. 



