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Part III. — Tenth Annual Report 
its position had evidently seriously impeded the movements of the tail, 
the lower lobe of the caudal fin, as already stated, being considerably 
lacerated — an irregular triangular piece about 2 inches across the base and 
2 inches in height having, in this way, been removed. 
II. Microscopical Features op the Tumour. By Dr J. Lindsay 
Steven. 
The naked eye appearances of the tumour, which was of the size of a 
small apple, were those of a melanotic sarcoma. Its ulcerated surface 
showed intensely black areas, in the midst of white tissue, of a gelatinous 
character. A thin slice was taken from the interior, and hardened in 
absolute alcohol. Sections were made, and these were examined unstained 
and stained in Picro-Lithium Carmine, Logwood, and in Eosine and Log- 
wood double stain. 
In section the pigmented and non-pigmented areas were sharply 
defined, though branching pigment corpuscles occasionally passed over the 
lines of demarcation. The branched corpuscles in the non-pigmented 
parts had an appearance suggestive of delicate tubular spaces in which the 
granules were massed, the spaces ramifying between the cells of the 
tumour. So dense was the aggregation of black corpuscles in the dark 
areas that the sections were quite opaque, and transmitted light could only 
at occasional points be seen to penetrate them. At the margin of these 
areas the coloured corpuscles appeared to be somewhat stellate, as shown in 
the drawing (Plate XVII. fig. 3) made by Dr T. K. Monro, with the aid 
of the camera lucida, and were of an inky blackness. In the midst of the 
densely pigmented areas, moreover, appearances were seen which suggested 
the presence of delicate tubular spaces, in which the colouring matter was 
accumulated. 
The non-pigmented portions exhibited thin- walled blood vessels contain- 
ing nucleated oval corpuscles, and ramifying in all directions : but the 
main mass of the tumour consisted of small spindle-shaped cells (PI. XVII. 
fig. 2) nucleated, and in some areas arranged in parallel rows, not unlike 
fibrous tissue. Some cells were rounded rather than spindle-shaped : but 
the tumour may, on the whole, be described as a small spindle-celled 
melanotic sarcoma. 
III. On an Internal Tumour from the Abdomen of a Cod. 
By Professor Prince. 
A remarkable tumour from the perivisceral cavity of a large cod was 
received at the St Andrews Marine Laboratory on May 30th. It weighed 
no less than 15 J oz., though it was in a partially dried condition, having been 
procured two days previously. 
It was of a yellowish-white colour, extremely smooth, and not unlike a 
small bladder of lard in appearance. In shape it was rudely pyriform, 
10 inches in circumference at the widest part, and over 5 J in. long. No scar 
or evidence of attachment was perceptible on its exterior. At the narrow 
end a round terminal depression occurred, and deep furrows appeared upon 
the sides, four of these exhibiting apertures from which red mucus was 
exuding. The other depressions were evidently slits recently closed, and 
these could be readily opened by inserting the handle of a scalpel. Upon 
dissecting away part of the wall, which was of a dense white fibrous nature, 
more compact externally arid forming an inseparable outer cuticle, the 
