TRANSMISSION OF MALFORMA TIONS. \ 9$ 



from which this fish was taken should be dragged for 



the purpose of ascertaining the existence of other fish 



similarly affected. When this was 



done several fish of the same 



species were taken with tumours 



of the same kind growing upon 



them. 



In this case it is reasonable to 

 suppose, in the absence of evidence 

 to the contrary, that the inhabi- 

 tants of the pond being limited, 

 the chances of this defect being 

 transmitted were greatly in- 

 creased. This view is equally 

 applicable to the case of the tail- 

 less trout of Islay. 



The curious condition of the 

 skeleton of the fish Chcetodon, 

 described by William Bell in the 

 " Philosophical Transaction," 1 793, 

 deserves mention in connection 

 with this subject. He writes : 

 " The fish is frequently caught at 

 Bencoolen and several other parts 

 on the west coast of Sumatra. 

 The skeleton is very singular, FlG - IO S- ~ A bone from the fish 



Choetodon with a tumour, 



many of the bones having tumours, shown in section, attached 

 which in the first fish Mr. Bell saw to !t (Natt size>) 

 he supposed to be exostoses arising from disease, but 

 on dissecting a second found the corresponding bones 

 had exactly similar tumours, and the fishermen informed 



