214 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



and the presence of melanin granules in the lymph or 

 blood vessels. 



It is evident, then, that in this specimen we have to 

 deal with a generalisation of the affection, since most 

 parts of the flesh of the wings show the presence of the 

 tumour. That this generalisation was affecting the 

 health of the fish was very apparent from the general, 

 bad condition of the flesh. Unfortunately, the fish had, 

 as usual, been gutted at sea, so that there was no 

 opportunity of examining the viscera. 



The minute structure of the tumours presents 

 several features of interest. In any specimens of skates 

 and rays, presenting sarcomatous conditions, which I 

 had seen before, the morbid growth affected only the 

 integumentary connective tissues. It is true that this 

 growth may have been massive, that is an extra- 

 ordinary hypertrophy of the connective tissues 

 may have occurred ; still the underlying muscles have 

 always been free from the morbid growth. In this 

 specimen, however, large blocks of muscular tissue have 

 disappeared, and their places have been taken by the 

 sarcomatous tissue — as in Text-fig. 1. 



Fig. 2, PI. II, represents a section through the 

 margin of one of the smaller tumours — such a section as 

 is shown to the left in the lower figure in Text-fig. 1. 

 On the right, in fig. 2, we see the almost unaltered 

 muscle fibres cut in transverse section, and on 

 the left a relatively massive aggregation of sarcomatous 

 tissue. Even in the latter there are spaces, and these 

 spaces contain isolated muscle fibres. On the right, the 

 malignant tissue, indicated by its melanin contents, is 

 seen invading the connective tissue between the fibres. 

 In the same section of which fig. 2 is a part, the 

 central part of the tumour is entirely free from any 



