NEW GROWTHS IN FISH. 285 



and so is perhaps related to the sarcomata, Lut until more extended 

 observations can be made on other cases, this must remain as the 

 merest surmise. 



HAEMAXGIOMATA OF A SPOTTED RAY (EAIA MACULATA) 

 AND OF A GURXAED (TRIGLA LINEATA). 



These tumours were accompanied by the presence of parasitic cope- 

 pods ; unfortunately in each case the body of the copepod had been 

 broken off, leaving merely the haustoria imbedded in the growth, so 

 that their species could not be determined. 



In the case of the gurnard a small reddish soft tumour was present 

 on the inner surface of the operculum ; in the case of the ray, a similar 

 tumour was present on the skin in the mid-ventral line of the body at 

 the level of the fifth gill arch. 



Sections showed a condition identical with the capillary Haeman- 

 giomata found in man. The tumours consisted of an irregular mass of 

 dilated thin-walled capillaries filled with blood cells : the haustorial 

 branches of the parasites could be easily recognised in the middle of 

 each tumour. 



In these cases it is impossible to say whether the tumours developed 

 first, and then were attacked by the parasitic copepods, or whether they 

 represent a peculiar type of reaction on the part of the host to the 

 presence of the parasite. The former alternative would seem the 

 more probable, since in by far the majority of cases of infection by 

 parasitic copepods, little or no sign of an inflammatory reaction on 

 the part of the host is present. 



A PIGMENTED TUMOUR OF A MACKEREL (SCOMBER 

 SCOMBER) OF INFLAMMATORY ORIGIN. 



This fish, a male, 11 inches in length, caught at Plymouth, showed a 

 large diffuse swelling on its side, situated about 3 inches from the 

 tail. The surface of the skin was not broken, but was very darkly 

 pigmented. 



On cutting through the skin and deep into the subjacent muscular 

 tissue, the cut surface appeared soft, haemorrhagic and degenerated, 

 and was of a brownish colour ; in places small black specks, due to the 

 aggregation of pigment granules into masses, were visible to the naked 

 eye. The swelling was not circumscribed, but passed imperceptibly 

 into the surrounding normal muscular tissue : the vertebral column 

 was not affected. 



Sections of the diseased area presented an appearance superficially 

 resembling a melanotic sarcoma, so much so that without some 



