140 



WEALDBN AND PURBECK FOSSIL FISHES. 



Mantell to have been obtained from the Chalk of Lewes, are generally regarded as 

 Wealden fossils (S. J. Mackie, The Geologist, vol. vi, 1863, p. 242, and A. S. 

 Woodward, Catal. Foss. Fishes, Brit. Mus., pt. i, 1889, p. 275). A renewed 

 examination of these fragments, however, suggests that they are from a ferruginous 

 concretion in the Chalk, and not from any Wealden deposit. As already suspected 

 by M. Leriche (Mem. Soc. Geol. Nord, vol. v, 1906, p. 91), they are parts of the 

 dorsal fin-spine of a Chimaeroid fish ; but they still remain unique. The anterior 

 border of the spine is less compressed to an edge than usual, and it is ornamented 

 with a few large and irregularly arranged tubercles (not shown in Agassiz' figures). 

 The longitudinal ribbing of the lateral faces is coarser and more marked than in 

 any other known Chimasroid spine. The specimen may perhaps belong to a 

 species of Ischyodus. 



Hybodus subcarinatus, Agassiz (p. 10). 



Lepidotus mantelli, Agassiz (p. 36). 



According to Mr. J. Wilfrid Jackson, the type specimens of Hybodus sub- 

 carinatus and the so-called Tetragonolepis mastodonteus (= small dentary of 

 Lepidotus) are in the Cumberland Collection in the Manchester Museum. 



Fig. 41. — Lepidotus minor, Agassiz ; restoration with amended dorsal and anal fins, to replace the restoration 



given in Text-fig. 14, p. 28. 



Lepidotus minor, Agassiz (p. 27). Plate XXVI, fig. I. 



Dr. F. Du Cane Godman, F.R.S., has lately given to the British Museum the 

 large specimen of the stout variety of Lepidotus minor, from the Middle Purbeck 

 Beds of Swanage, shown of one-third the natural size in PI. XXVI, fig. 4. It is 

 important as displaying the complete dorsal fin, which is proved to have been 

 wrongly drawn in the restoration of the species in Text-fig. 14, p. 28. A new 

 restoration with the dorsal and anal fins amended is accordingly given in Text- 

 fig. 41. The specimen is much lateral]) compressed by crushing, so that the left 



