342 Becords of the Indian Museirm. [YoL. XY, 



of the body. On October 10th three fish were found to be affected. 

 These were preserved. The present account deals with the natiire and 

 structure of the outgrowths noted above. Observations on the remain- 

 ing 17 fishes, which are still living under the same conditions (April 1st). 

 are being continued. 



2. Technique. — The outgrowths were cut off from one of the living 

 fish and preserved in corrosive acetic solution. This fish, along with 

 the two others, was preserved in 90 per cent, alcohol. One of the 

 outgrowths was teased out and permanently mounted in dilute glycerine. 

 Sections of the tumour were also cut with a Minot's microtome by the 

 ordinary paraffin method. These were stained with Heidenhain's iron 

 haematoxylin followed by eosin. 



3. Appearance and occurrence. — The outgrowths are remarkable in 

 having a mulberry-shaped appearance. They are much divided, nodular 

 masses (fig. 4) attached to the body of the fish by very short stalks. 

 They vary considerably in appearance and occur in various situations. 

 In one fish two masses were present on the left side, one attached 

 a little above the operculum and the second about half an inch in front of 

 the first (fig. 1). A very small one was developing below the eye, whilst 

 a fourth was present on the mid- ventral line in the region of the throat. 



In the second specimen (fig. 2) a large .outgrowth had developed 

 above the right eye. A similar but very much smaller one was present 

 over the left eye. A third was to be seen on the right side, about half an 

 inch behind the eye. A small outgrowth was hanging pendant from the 

 upper jaw on the right side ; another from the lateral edge of the oper- 

 culum on the right side. A small one was also present on the fin- 

 rays of the ventral fin. 



In the third fish (fig. 3) the main outgrowth was on the tip of the 

 snout. A smaller one y-as attached to the ventral edge of the operculum, 

 on the ventral side, near the throat. Another was situated a little in 

 front of the pelvic fins, whilst still another large outgrowth was to be 

 seen on the base of one of the spines of the dorsal fin. Another small 

 one was also present on the upper margin of the caudal fin. 



4. Structure. — The tumours are undoubtedly infiltrating epithelial 

 neoplasms, or malignant epitheliomas, designated as Carcinomas by 

 Orth. They are of an alveolo-tubular type, the greater proportion 

 of these being solid. On teasing out a portion of the tumour it is seen 

 to consist of large polygonal cells filled up almost entirely with large 

 numbers of small glistening drops of colloid substance. The nuclei 

 of these cells could not be distinguished in the glycerine mounts. They 

 were, however, seen in the stained sections. The greater portion of the 

 carcinoma is of a regular formation. The epithelium is closely packed, 

 but very extensively vacuolated. Here and there, particularly where 

 the outgrowths arise from the external surface, we find that the alveoli 

 have coalesced to form large tubular cavities. These tubular cavities 

 .are lined by epithelium which also is vacuolated. Around the vacuoles, 

 colloid material can be seen as deeply staining granules filling up the 

 rest of the epithelial cells. The core of these wart-like outgrowths 

 consists of connective tissue ; pigment corpuscles arc present both in 

 the connective tissue and in the epithelial cells, 



