172 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



themselves. Thus one would expect the two trawled samples 

 to represent one race, but these two samples differ markedly. 

 The same thing may be seen in the samples from Port Erin. 



At first sight this might be regarded as against any 

 division into races, but there are two defects in the figures 

 which make any such conclusion untrustworthy. 



In the first place, the sampling has, in many cases, been 

 quite insufficient. This is especially the case in regard to the 

 fish from the Welsh Coast. The samples for the 1913-1914 

 season are much too small, and while those for 1914-1915 

 are better, they are still, I consider, insufficient. This seems 

 to have been a bad season on the Welsh coast ; it was impossible 

 to get large samples, and no fish were received after the end 

 of 1914. In the second place, many of the samples were 

 kept in cold storage until time allowed of their being examined. 

 This, I am now sure, renders any measurements made upon 

 such samples quite untrustworthy. I do not believe that 

 any correction can be applied to compensate for the distortion 

 caused by this method of preservation. This is the only 

 conclusion I can draw from my own results, and Williamson's* 

 experiments upon mackerel point to the same thing. Future 

 samples must be examined in a fresh condition. It is possible 

 that other modes of preservation may not be open to the 

 same objection. Heincke applies a correction to some of his 

 samples which were preserved in spirit. But I think that, 

 until direct experiment has shown that such a correction gives 

 satisfactory results, all measurements made on preserved 

 fish must be regarded with suspicion, and not used for com- 

 parison with measurements made on fresh material. 



This does not apply, of course, to the examination of 



skeletal characters, such as - vertebrae. So far I have not 



examined the vertebrae of a sufficient number of fish to be 



able to draw any conclusion from them. The keeled-scales, 



* Fishery Board, Scotland, 18th Annual Beport. 



