SEA-FISHERIES LABORATORY. 123 



attached by a narrow base to the integument covering 

 the eye, and no other part of the latter organ was 

 involved. It was yellow- white in colour, and very hard 

 and compact. 



The tumour on the head was very similar in appearance 

 to the melanotic spindle-celled sarcoma described by me 

 in last year's Report*, but it was larger and softer, and 

 the metastases in the fish now described were not present 

 in the former specimen. In both cases there was 

 emaciation of the fish. In the tumour now being 

 described, diagnosis is more difficult than in the Port 

 Erin specimen, for necrosis, and secondary changes, have 

 made the tissue far less characteristic in appearance ; and 

 owing to the overgrowth of the tumour itself on the 

 surrounding skin it is far less easy to trace the transitional 

 integumentary tissues. The neoplasm, however, involves 

 the connective tissues of the skin, mainly the layer 

 between the epidermis and the strong and coarse fibrous 

 bundles that lie underneath : this, and to a less extent, 

 the other connective tissue layers deeper down, are the 

 regions of active proliferation. 



Fig. 5, PI. II, represents a part of a section not far 

 from the growing region of the tumour. The fish had 

 necessarily been preserved in formalin so that the fixation 

 was not good. The sections were stained in various ways, 

 on the whole methyl-blue-eosin, or Ehrlich's haema- 

 toxylin, followed by eosin, gave the best results. In the 

 older parts of the tumour the tissue elements are greatly 

 broken down, so that it is very difficult to identify them. 

 The whole tumour is deeply impregnated with melanin 

 granules, and these further obscure its structure, even 

 when much of the pigment has been removed by a 



* Rept. Lancashire [Sea-Fish. Laby. Liverpool, for 1910 ; in Trans. 

 Liverpool Biol. Soc, VoLJ,25, 1911. 



