442 Mr Mcintosh, On Variation in the Norway Lobster. 



Table II shows the proportion of normal and abnormal males 

 among the specimens obtained from both Forth and Clyde. From 

 this it is seen that in each place the B, C, D, and E arrangements 

 occur. Although the F arrangement was not found in the Forth 

 lobsters, the corresponding arrangement of an extra aperture on 

 the left (instead of the right) second walking leg was noted. 

 Further, there were found in the Forth one specimen with a total 

 of seven apertures, two with six, and five with five apertures, 

 while none of the Clyde specimens had more than four. 



Table II. 



Mr Marshall, however, examined, although he did not include 

 in the figures given above, 80 specimens which were caught off 

 the Isle of Man in the mouth of August, 1901. He was specially 

 struck with the fact that he found among these only one abnormal 

 male. " The number," as he remarks, " is, of course, not large 

 enough for any definite conclusions to be based upon it ; but in 

 view of the fact that I never obtained even smaller batches from 

 the Forth area without finding a much higher percentage of 

 abnormality, the presence of only a single abnormal specimen 

 among the Isle of Man lobsters may point to the percentage 

 being related to the locality." The same remark may be held to 

 apply, though with less force, to the case now under consideration, 

 but the results so far obtained point distinctly to the conclusion 

 that the very marked difference is a local one. Mr Marshall 

 informs me that in the specimens (procured from the same source) 

 which he has examined since the publication of his paper, the 

 high percentage of abnormality therein recorded is almost fully 

 maintained. It ought to be added that the normal apertures 

 were present in every specimen examined, and that while the 

 variation in the male apertures was as stated, no female was 

 found with additional apertures. 



