118 TEAXS ACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



5. Melanotic Sarcomata in the Skate (Baia bat is). 



Two spef'imens of Skate containing such growths 

 were received during 1911. One was part of the " wing," 

 or ])Pctoral fin, of a very large fish cauglit oif the Blaskets 

 (County Kerry, Ireland) in loO fathoms of depth. The 

 tumour was a very small one and was not sectioned. 

 The other specimen was also the wing of a v^kate, caught 

 by a Fleetwood steam trawler wlien fishing oft Dubh 

 Artach Light (west coast of Scotland) in about 82 fathoms 

 depth. This specimen was received in a fresh condition, 

 and ])ortions of the affected tissue were fixed in Zenker's 

 fluid, in vom Rath's fixative, and in Bouin's fixative. 

 Sections were stained in iron haematoxylin, methyl- 

 bkie-eosin, and by other methods. The fixation in 

 vom Rath's fluid was the most satisfactory. In some 

 cases the tissues were decolorised by prolonged soaking 

 in hydrogen peroxide. The melanin is rendered colour- 

 less by this reagent, but the sections are very easily 

 detached from the slide during subsequent manipulation. 



This latter tumour was a large, rather irregular 

 growth in the middle of the dorsal surface of the left 

 ])ectoral fin. It measured about 10 by 6 cms. and was 

 raised u]j above the general surface of the skin about 

 1 cm. Its surface was flat, but rather rubbed and 

 injured, and there was also some degree of general 

 softening, due to autolysis in the central parts of the 

 tumour. It was veiy soft everywhere, and was extremely 

 difficult to cut ill the fresh condition. It was dense black 

 in colour, and the pigmentation extended for some 

 distance on to the adjacent parts of the integument. 

 There were several smaller growths on the lest of the 

 " wing," and some of these were true metastases, 

 being distinctly raised up. Others were apparently only 

 pigment patches. One of the more obvious metastatic 



