sea-fisheries laboratory. 291 



Various Fish Tumours. 



(1) A Benign Tumour in the Plaice. 



A plaice of 16J inches long, a female in very fair condition, 

 was sent to us by Mr. King, the Collector of Statistics at 

 Yarmouth. The fish has a very typical tumour on the dorsal 

 fin, on the coloured side. The growth is about 3| cms. in 

 diameter, and is raised up from the general surface of the fin 

 about 3 cms. It is nearly spherical, except that it is a little 

 flattened in the same plane as that of the fish. It is pigmented 

 very much in the same way as the fin and there are several 

 very noticeable blood vessels running just beneath its surface. 

 It is firm, but elastic. It has all the appearance of a human 

 " wen," such as one sees sometimes on a man's neck, except 

 that the fish tumour has a rather narrow attachment to the 

 part on which it is situated. 



Sections show the structure to be that of a typical fibroma. 

 At the periphery there is no proper skin, resembling that of 

 the fish : whatever cuticle there is is rather transparent. 

 Beneath the surface there is a layer of strong elastic tissue 

 and on the surface itself this merely becomes rather more 

 compact than it is in the deeper layers. There is a very definite 

 " capsule " made up of this dense elastic tissue, and below 

 this, and occupying the central part of the tumour, there is a 

 loose connective tissue, the fibres of which are wavy, but run, 

 on the whole, in laminae concentric with the surface. Here 

 and there are a few small blood vessels and capillaries, and 

 sometimes a few rounded, connective tissue cells, but otherwise 

 the histology presents do remarkable features. 



(2) Sarcoma in a Haddock. 



The specimen described here was sent to me by Mr. F. 

 Stokes, Port Sanitary Inspector at Grimsby. It was a haddock 

 of large size caught by a Grimsby codman and landed at that 

 port. It is of some interest because very much the same 



