34 WEALDEN AND TURBECK FOSSIL FISHES. 



more slender forms (Text- fig. 14). The flank-scales in the abdominal region are 

 nearly always feebly and coarsely serrated, but the serrations are usually restricted 

 to the lower portion of each posterior margin ; the scales of the lateral line are 

 also often notched at the posterior margin, and a varying number are pierced by 

 a sini])le foramen for the passage of the slime-canal. As the serrations of the 

 flank-scales disappear towards the caudal region, the postero-inferior angle of 

 each scale tends to become produced into a slender point, and this ma}^ even be 

 strengthened by a slight ridge (B. M. no. 19006). Towards the dorsal and ventral 

 borders, and in the hinder part of the caudal region, the scales become slightly 

 broader than deep ; and the third row from the dorsal border, between the occiput 

 and the origin of the dorsal fin, is marked at intervals with the orifices of an upper 

 slime-canal. The dorsal ridge-scales from a point shortly behind the occiput to 

 the origin of the dorsrd fin (accidentally removed from the original of PI. VI, but 

 seen in PI. VII, fig. 4, and in Text- fig. 14), are relatively large and pointed, and 

 form a conspicuous imbricated row ; there are also two or three enlarged ridge- 

 scales, not so deeply imbricating, at the origin of the caudal fin above and below. 

 The three enlarged scales, with denticulated posterior margin, surrounding the 

 anus just in front of the anal fin, are well shown somewhat displaced in PI. VI. 

 At the base of the fulcra of the dorsal fin about four scales in a regular row are 

 elongated in the direction of the fin-rays ; at the base of the caudal fin small 

 elongated scales are similarly related to the rays, while a notch in the end of the 

 caudal pedicle marks the limit of the triangular remnant of the upper caudal lobe. 

 The scales of the abdominal region are united in the usual manner by a 

 complicated overlap and a peg-and-socket articulation. On the flank, the wide 

 overlapped margin of each scale is produced at its upper angle into a large 

 bluntly rounded process, at its lower angle into a smaller acute process (PI. VII, 

 fig. 5) ; while there is sometimes a minute prominence in the excavation between 

 the two {e. (j. in B. M. no. P. 4989 a). In the ventral scales (PI. VII, fig. 5 h), the 

 antero-superior process becomes especially large, produced upwards as well as 

 forwards, and the antero-inferior process disappears. In all these scales, the 

 peg-and-socket articulation, strengthened by a vertical ridge, is also present ; in 

 the caudal scales only the strengthening ridge, more or less widened, remains. 

 Horizon and Locallti/. — Middle Purbeck Beds: Swanage, Dorset. 



2. Lepidotus notopterus, Agassiz. Plate VII, fig. 6. 



1835-37. Lepidotus notopterus, L. Agassiz, Poiss. Foss., vol. ii, pt. i, p. 257, pi. xxxv. 

 1850. Lepidotus notopterus?, V. Thiolliere, Aub. Sci. Phys. Nat. Lyon [2], vol. iii, p. 138. 

 1852. Lepidotus notopterus, F. A. Quenstedt, Handb. Petrefakt., p. 197, pi. xv, fig. 4. 

 1863. Lepidotus notopterus, A. Wagner, Abhaudl. k. bayer. Akad. Wiss., math. -phys. Cl., vol. ix, 

 p. 628. 



