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Part III. — Eleventh Annual lieport 



ring singly, being white, glistening spheres from 1 to 1*5 mm. in diameter. 

 Between them is a varying amount of tissue, specially abundant near the 

 base of the tumour, and consisting either of fibrine and leucocytes, or of 

 more or less advanced connective tissue, in one case of myxomatous tissue. 

 The small, round, nucleated cells described by Professor M'Intosh are in- 

 variably present, and are very abundant where there is any considerable 

 amount of interstitial tissue. Young blood-vessels are usually present, 

 and haemorrhages from these, which seem to occur frequently, owing 

 probably to the mechanical irritation to which these masses are exposed, 

 may leave red corpuscles or pigment in the adjacent tissue. Professor 

 M'Intosh says that the tumours bleed freely when interfered with in the 

 living condition. 



These round elements, though varying slightly in size, do not appear to 

 grow from a very small size ; and serial sections show that all of them are 

 fairly constant in this respect. 



No noticeable pathological condition can be found constantly present 

 in all fish which are affected by the multiple tumours, and no trace of 

 bodies like them occurs in any of the viscera, or muscles, or on any mucous 

 membrane. 



The elements of these tumours present so close a resemblance to eggs 

 laid beneath the skin, with subsequent organisation of a mucous substance 

 between them, or of blood-clot formed during oviposition, especially since 

 an appearance of a developing blastoderm is occasionally present, that 

 there would not be any doubt as to their nature, if it were not that no 

 wound can be found through which they could have been introduced, that 

 it is difficult to understand how any animal could force so large a mass of 

 eggs beneath the skin so as to form a pedunculated tumour, that they 

 seem to occur to some extent all the year round, and that it is rare to find 

 one showing anything like development. On the other hand, they show 

 no resemblance to any known diseased condition, being plainly not re- 

 tention cysts, and being unlike any known protozoon or protophyte. No 

 micro-organisms are present in the cysts or surrounding tissue. Professor 

 M'Intosh found within one of these tumours Diplozoon paradoxieum in 

 the adult united condition, but this is the only case in which such a para- 

 site has been found. 



Plate XVII. 



Fig. 1. Tail of flounder with multiple tumours. 



Fig. 2. Large tumour from operculum of flounder. 



Fig. 3. Section of above. Zeiss Oc. 1, Obj. A. 



Fig. 4. Section of single cyst in situ. Zeiss Oc. 1, Obj. A. 



Fig. 4a. Part of above. Zeiss Oc. 1, Obj. D. 



Fig. 5. Section of large tumour. Zeiss Oc. 1, Obj. F. 



Fig. 6. Skin of Montagu's sucker, showing contraction of chromatophores. 



Fig. 7. Rod-like bodies from affected portion of skin. 



3. On a Tumour from a Tunny. By George Sandeman, St Andrews 

 Marine Laboratory. 



This tumour (Plate XII. fig. 1) was an egg-shaped mass taken from a 

 tunny captured in the Forth, and described in the Fourth Annual Report of 

 the Board, and in the annals of Natural History for April 1886, p. 206. Its 

 surface was very regular, with small rugae running longitudinally. The 

 length was 1J inches and diameter J inch. There was no definite 



