BRITISH FOSSILS. 



3 



order from the back. The surface of all the scales is smooth on the 

 anterior portions. The posterior margins are finely serrated, and 

 the surface of the scale in the vicinity of the serrations is finely 

 striated ; the stripe agree in number with the serrations, being 

 due to the persistance of the marginal serrations of earlier periods 

 of growth. The scales are imited by long processes on the under- 

 surfaces, very similar to the corresponding parts of the scales of 

 PJiolidophoriis, and differing entirely from those of Lepidotus or 

 Ophiopsis. 



Affinities. — The affinities of the genus Histionotus have been 

 considered at the commencement of this article. I would only 

 add that, on the whole, it seems to be more nearly allied to Pho- 

 lidophorus than to any other genus. It may, perhaps, hereafter 

 be thought advisable to remove to this genus some of the fishes 

 with long dorsal fins now grouped with the Pholidophori, rather 

 than to the genus OpMopsis, as suggested in the description of 

 Opldopsis hreviceps in the Sixth Decade. 



Locality. — The specimen described above, and figured in the 

 accompanying plate, was procured by me in the course of the 

 present year from one of the quarries of Purbeck stone at Swanage. 



Explanation of Plate, 



Fig. 1. Histionotus angularis, size of nature. 



Fig. 2. Scales, magnified. 



Fig. 3. Under surface of scale, magnified. 



P. DE M. Grey Egerton. 



May 1853. 



