164 MR. W. BATESON ON THE COMMON PILCHARD. [Mai*. 6, 



illustration has been lent to us. This bird has now moulted its 

 nestling-plumage altogether, and has assumed the first feather- 

 plumage, in which it is nearly of a uniform black. 



The young bird was probably not more than 2 or 3 months old 

 when received, and therefore would appear to remain about 7 or 

 8 months in its nestling-plumage. 



Mr. W. Bateson exhibited six specimens of the Common Pilchard 

 (Clupea pilchardus) showing variation in the number and size 

 of the scales. The specimens had been received from Mr. 

 Matthias Dunn, of Mevagissey, Cornwall. In each of them the 

 scales over a greater or less area of the body were smaller and 

 more numerous than in the normal fish. Similar specimens were 

 exhibited to the Society by Mr. Bateson in 1890 and had been 

 described in the Proceedings l as examples of abnormal repetition 

 of parts. In that paper reference was made to an account of a 

 similar specimen that had been given by the late Mr. P. Day", 

 who took a different view, being of opinion that the fish was 

 a hybrid between the Pilchard and the Herring. For reasons 

 then given it was urged that the evidence of hybridity was unsound, 

 and it was represented that the abnormality was more probably 

 due to variation. 



The new cases fully bore out the view then taken. Except in 

 the matter of the scales, each of the six examples was in all re- 

 spects a true Pilchard, having the normal sculpture on the opercula, 

 the high number of gill-rakers characteristic of the Pilchard, and 

 the histological features normally found in the scales of the 

 Pilchard. In the matter of the gill-rakers the lowest number seen 

 in the abnormal fishes was 70 and the highest S9, most of them 

 having about 78. The numbers seen in normal Herrings are 

 considerably lower than these. 



In four of the new specimens the small abnormal scales extended 

 over the posterior half of one side only. In one specimen both 

 sides were almost uniformly covered with the small scales. In the 

 sixth specimen the posterior half of one side showed the small 

 scales, and on the other side there was in about the middle of its 

 length a circular patch of very small scales, the remainder of the 

 scaling being normal or nearly so. Unfortunately the specimens 

 had been somewhat rubbed and the precise numbers of the scales 

 cannot confidently be given. Speaking in general terms, it may 

 be said that in the areas of abnormal scaling the size of the scales 

 was about half that of the normal scales. All the specimens 

 were well grown and in good condition, ranging from 7 to 8| inches 

 in length. 



1 Proc. Zool. Soc. 1890, p. 58G. 



2 Op. cit. 1887, p. 129, pi. xv. 



