Fishes. 4713 



"Lateral line precisely mesial in the Castle Loch vendace, but 

 one-eighth nearer the dorsal line than the abdominal line in the 

 Mill Loch. 



" A section shows both these specimens to be female, with the ovary 

 more fully developed in the Mill Loch vendace ; the liver is evidently 

 larger in the vendace of the Mill Loch : these differences, however, will 

 not account for the great additional weight of 4 drs., and which evi- 

 dently arises from the greater depth and thickness of the Mill Loch 

 vendace. This greater depth and thickness of the body, and the larger 

 head, seems to me to constitute the only specific differences between 

 these two fishes. The difference in colour is very striking ; but this 

 seem to me to depend on the greater number of minute black spots 

 of the rete mucosum in the Mill Loch vendace : the dark shade is so 

 strong on the head as to obscure almost, if not entirely, the brain ; and 

 thus the peculiar and much-dwelt-on heart appearance observed in the 

 Castle Loch vendace is not seen in that of the Mill Loch. The scales, 

 which I took from the lateral line and near it, of both specimens pre- 

 sent precisely the same appearance when placed under the microscope : 

 I counted 30 rays on that part of the scale, in both specimens, which is 

 exposed : the number of rings on the part concealed by the super- 

 imposed scale is greatly more." 



The largest vendace I have ever seen was 9 inches in length. 



Another delusion in respect of the vendace was the supposition that 

 the males lived apart from the females in deeper water, and hence be- 

 yond the reach of the net. Like everything else in the history of the 

 fish this also seemed a delusion ; for the net being drawn in the Castle 

 Loch of Lochmaben, and near the castle, in presence of Mr. Murray 

 and myself, of fifteen vendace which I examined nine were females and 

 six males : this was in October. Nevertheless, T feel disposed to think 

 that the males are not so numerous as the females, for of forty taken in 

 the Mill Loch at one time only two were males. The males are lighter 

 coloured than the females. 



(Thus terminated a popular delusion which had no doubt maintained 

 its ground for centuries. The discovery of the food of the vendace, 

 and of countless millions of other fishes to be spoken of immediately, 

 was a gift of the microscope to science : it illustrates and perhaps ex- 

 plains many obscure points in the natural history of such fishes, and 

 may one day lead to important results. — Added to the original MSS. 

 April 20, 1855.) 



