2 



BRITISH FOSSILS. 



lepis. I am cognizant of several species, probably referable to this 

 genus, all of which will be noticed in the sequel. 



Description. — The beautiful little fish which I have selected as 

 the type of the genus was found by Mr. Bristow in the Middle 

 Purbeck beds at Apsel Lane, north of Sutton Mandeville. It 

 measures two inches in length from the nose to the extremity of 

 the tail, by three-tenths of an inch in depth. The latter measure- 

 ment is taken at a point midway between the pectoral and anal 

 fins, from which point the body tapers symmetrically to the tail. 

 The head measures four-tenths of an inch in length. The mouth is 

 small and opens upwards, as in Thrissops and Leptolepis. The 

 relative size and position of the orbit correspond also with these 

 genera. The opercular bones are of moderate size and smooth 

 exterior. The rays of the pectoral fin are strong in relation to the 

 size of the fish. Their number cannot be ascertained. The ventral 

 fins are small, and situated midway between the pectoral and anal 

 fins. The dorsal fin commences at a point two-thirds of the dis- 

 tance from the nose to the fork of the tail. It contains ten delicate 

 rays, single for half their length, and then bifurcated and trans- 

 versely articulated. They are preceded by a few elongated fulcral 

 scales. The anal fin is opposed to the dorsal fin. It contains 

 twelve rays, rather distant from each other. They correspond in 

 character with those of the dorsal fin. The anterior ray is bordered, 

 a character probably also common to the dorsal fin. The caudal 

 fin is deeply cleft. The upper lobe is invested with scales at its 

 base, and contains nine principal rays, closely set at their insertion. 

 The lower lobe, is also composed of nine rays, more distant from 

 each other than those of the upper lobe. All the rays have frequent 

 transverse joints, more numerous on the lower than the upper lobe. 

 The borders of both are fringed with fine elongated fulcral scales. 

 The scales are smooth. Those on the back, belly, and tail are 

 small and lozenge-shaped. The remainder of the body is covered 

 with a single row of high, narrow scutes, inclining backwards 

 and downwards in slightly sigmoid curves ; each scale has a broad 

 elevated band extending from the apex to the base of the inner 

 surface (fig. 9). It is broader above than below, and terminates 

 upwards in a short process, which connects it with the scale next 

 above it in the series. 



Locality. — This, the only specimen I have seen of Pleuropholis 

 attenuatus, was found by Mr. Bristow in the Middle Purbeck beds 

 at Apsel LanCj north of Sutton Mandeville. 



