ENCHODUS. 57 



1. Enchodus lewesiensis (Mantell). Plate XIV, figs. 1—8 ; Text-figure L3. 



1822. Esox lewesiensis, G. A. Mantell, Foss. S. Downs, p. 237, pi. xxv, fig-. 13, pi. xxxiii, figs. 2—4, 



pi. xli, figs. 1,2. 

 1835-44. Enchodus halocyon, L. Agassiz, Poiss. Foss., Feuill., p. 55, and vol. v, pt. i, p. (14, pi. xxv c, 



figs. 1—6, 8—16 (non fig. 7). 

 1850. Enchodus halocyon, P. Dixon, Geol. Sussex, p. 373, pi. xxx, figs. 20, 27, pi. xxxi, fig. 11. 

 1888. Enchodus levesiensis, A. S. Woodward, Proc. Greol. Assoc., vol. x. p. 315 (in part), pi. i, fig. 5 



(non fig. 6). 

 1901. Enchodus lewesiensis, A. S. Woodward, Catal. Poss. Fishes B.M., pt. iv, p. 191, pi. xi, fig. 1. 

 — Enchodus annectens, A. S. Woodward, ibid., p. 195, pi. xi, figs. 4, 5. 



Type. — Imperfect mandible from one of the Turonian zones ; British Museum. 



Specific Characters. — The type species, with the mandible sometimes attaining 

 a length of 10 cm. The sides of the cranial roof and the outer face of the 

 mandible ornamented with numerous and closely-arranged sharp ridges, mostly 

 radiating and each bearing a series of small tubercles ; these ridges on the dentary 

 bone radiating from the symphysis, on the articulo-angular bone radiating from 

 the mandibular articulation. Palatine bone only slightly produced forwards as a 

 short cylindrical extension in advance of the ethmoid articulation, and the long 

 slender tooth, antero-posteriorly compressed, fixed at its extremity nearly at right 

 angles to the long axis of the bone ; the outer face of the premaxilla sparsely 

 ridged, with a slight tubercular ornament; dentary rapidly contracting almost to a 

 point at the symphysis, where it exhibits about three large irregular descending 

 processes ; the mandibular ramus considerably deepened behind, its maximum 

 depth nearly equalling one third of its total length ; about six large mandibular 

 teeth, all both slender and little curved, the foremost twice as large as any of the 

 others. Teeth much compressed, and some delicately striated, none conspicuously 

 serrated on the edges. Operculum nearly two-thirds as broad as deep, marked 

 by numerous sharp, radiating, tuberculated ridges ; suboperculum triangular and 

 nearly equilateral. 



Description of Specimens. — The type specimen of this species is an imperfect 

 mandible probably from a Turonian zone near Lewes, described and figured by 

 Mantell under the name of Esox leivesiensis. The hinder portion of its left dentary 

 exhibits the characteristic external ornament, and enough of the jaw is preserved 

 to indicate approximately its proportions ; but the fossil is very imperfect, the 

 symphysis being broken away in front of the large anterior teeth, and the outer 

 lamina of the dentary being entirely removed, except for the short space already 

 mentioned on the left side. The other three imperfect mandibles referred by 

 Agassiz to the same species under the new name of Enchodus halocyon (op. cit., 

 vol. v, pt. i, p. G^t, pi. xxv c, figs. 2 — 5) are evidently of the same form ; while 



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