36 WBALDEN AND PURBECK FOSSIL FISHES. 



the anal tin, behind tlie dorsal, is indicated by traces of fulcra and the bases of fin- 

 rays. The end of the caudal pedicle is deeply excavated at the base of the caudal 

 fin, and the stout npper lobe is considerably produced. The caudal fin-rays 

 exhibit the usual stoutness and close articulation, while the fulcra on the lower 

 margin are large though slender. 



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



3. Lepidotus maatelli, Agassiz. (Plate VII, fig. 7; Plates VIII, IX, X; Plate 

 XI, figs. 1—14; Text-figs. 13, 16—18.) 



1826. Figiu-e of dentary by T. Webster, Trans. Geol. Soc. [2], vol. ii, j;]. vi, figs. 5, 6. 



1827. " Scales of a Quadrangular Form," G. A. Mantell, Illustr. Geol. Sussex and Foss. Tilgate 

 Forest, p. 58, ]A. v, figs. 3, 4, 15, 16. 



1833. Lepidotus subdenticnlatus, L. Agassiz, Poiss. Foss., vol. ii, pt. i, p. 9. [Scales, afterwards 



referred to L. fittoni, Agassiz, iom. cit., p. 265 ; National Museum of Natural Historv, Paris.] 

 1833-37. Lepidotus mantelll, L. Agassiz, Poiss. Foss., vol. ii, pt. i, pp. 9, 262, pi. xxx, figs. 10 — 15 ; 



pi. XXX a, figs. 4 — 6 ; pi. xxx b, fig. 2 ; pi. xxx c, figs. 1 — 7. 

 1834-44. Lepidotus fittoni, L. Agassiz, Poiss. Foss., vol. ii, pt. i, j). 265, pi. xxx, figs. 4 — 6 ; pi. xxx a 



(excl figs. 4 — 6) ; pi. xxx & (excl. fig. 2). [Poition of fish, British Museum.] 

 1836-44. Tetragonolepis mastodonteus, L. Agassiz, Poiss. Foss., vol. ii, pt. i, p. 216, i)l. xxiii e, figs. 3, 



4 {non fig. 5). [Small dentarv.] 

 1841. Lepidotus manteJli, R. Owen, Odontogr., p. 69, pi. xxx, fig. 1 ; pi. xxxi. [Structure of teeth.] 

 1849. Lepidotus mantelli, W. C. Williamson, Pbil. Trans,, p. 444. [Sti'ucture of scales.] 

 1860. Lepidotus fittoni, J. E. Lee, Geologist, vol. iii, p. 458, |il. xii. [Structure of scales.] 

 1887. Lepidotus manteUi, W. Brauco, Abhandl. geol. Specialk.Preus.seii u. Thiiring. Sfaafen,vol. vii, 



p. 345, pi. iii, figs. 1, 2. 

 1895. Lejndotus mantelli, A. S. Woodward, Catil. Foss. Fishes, Brit. Mus., pt. iii, p. 108, text-figs. 



23, 24. 



Ti/pe. — Portion of fish; British IVIuseuni. 



Specific C]t(iracter!<. — A stout species attaining a length of about 1 metre. 

 Length of head with opercular apparatus considerably less than the maximum 

 depth of the trunk and contained slightly more than four times in the total length 

 of the fish. Snout acute and frontal profile somewhat bent ; external bones more 

 or less rugose or tuberculated ; parietal bones much less than half as long as the 

 frontals, which are about three times as long as their maximum width, very narrow 

 in front, and united throughout their length by a nearly straight median suture ; 

 orbit unusually small, with a relatively large circumorlntal ring, and the postorbital 

 plates much subdivided, the lowest and foremost plate of this series being the 

 largest. ]\louth small, the mandibular articulation below the middle of 

 the orbit; maxilla smooth, with deep rounded expansion behind; mandibular 

 symphysis very robust, the dentary being much horizontally extended to support 

 the large tootli-bearing splenial. Inner teeth very short and stout, smooth, usually 



