316 RF.V. S. GRAHAM BIRKS 



On the pre-axial border of the right pectoral fin-lobe there 

 appears a large scale which differs in size and shape from its 

 neighbours. This type of scale has been termed the basal 

 scale or fulcrum, but it is a feature which has apparently 

 received but little attention. In the generic type-specimen in 

 the Leeds Museum there is a large basal scale to be seen in a 

 position posterior to the two inferior opercular bones. Of this 

 scale Agassiz says : — " II est facheux que la grande ecaille du 

 cote gauche ne soit pas entiere, et surtout qu'une grande 

 partie de sa surface et de ses bords ait disparu. Cette piece 

 expliquerait bien des os enigmatiques de Burdie-House. La 

 presence d'une ecaille de cette grandeur pres des ventrales est 

 un fait tres-curieux ; car dans les Ganoides, les ecailles qui 

 avoisinent les nageoires deviennent ordinairement de plus en 

 plus petites." The scale is on the right side of the body, not 

 on the left as Agassiz indicates. This can be ascertained 

 either from the type-specimen in the Leeds Museum or from 

 the plaster casts {e.g. L.10132, Manchester Museum.) The 

 basal scales are clearly seen in the specimen from Idle 

 described by Prof. Miall on the pre-axial side of the right 

 pectoral fin and on the post-axial side of the left pectoral. I 

 have examined this specimen in the Leeds Museum, and I 

 feel little doubt that the fragment marked b at the bottom of 

 Prof. MialPs figure 5 was originally part of the same scale as 

 two fragments not illustrated in this figure, but shewn, in a 

 position anterior to the large fragment, in Prof. Miall's figure 1. 

 This seems to indicate fairly conclusively that this species has 

 large basal scales or fulcra on either side of the fin-lobes. 

 The specimen (L.10124) in the Manchester Museum further 

 exhibits very clearly the fin fringes and their relation to the 

 lobe of the fin, a feature which the splendid specimen in the 

 Leeds Museum fails to illustrate adequately. A description 

 of the specimen follows : — 



Portion of the body of Megalichthys hibberti in the 

 Manchester Museum (L.10124.) 



The specimen represents a part of the ventral surface of the 



