THE 



GEOLOaiCAL MAGAZINE. 



No. LXII— AUGUST, 1869. 



OiaiC3-I3r^^Xj -A-ISTICXjIBS. 



I. GEMS FROM PRIVATE COLLECTIONS, No. 2. 



On the GrENTTS JEcEMODUS PROM THE LlAS OF LtME EeGIS, 

 DORSETSHIKE. 



By Prof. Morris, F.G.S., etc., etc. 

 (PLATE X.) 



AMONG tlie many fossil remains of fishes obtained from the rich 

 Liassic deposits near Lyme Kegis, species of the genera Dapedius, 

 JEchmodus, Semionotus, and Pholidophorus are most frequently found 

 in a good state of preservation. These Lepidoid genera are chiefly 

 Liassic, two of the more long-bodied forms, Pholidophorus and 

 Semionotus, having species vfhich occur in the Purbeck (Phol. 

 ornatus) and the Chalk strata (Sem. Bergeri). Lepidotus, another 

 Lepidoid, ranges from the Lias through the intermediate Oolite and 

 Wealden strata into the Chalk, and according to Sir P. Egerton, 

 " the genus Lepidotus has the most extensive geographical range of 

 any genus of fossil fish." With the exception of Lepidotus, Prof. 

 Owen' classes the above genera under the Dapedoid family of the 

 order Lepidoganoidei, the genus Dapedius {D. politus) first noticed 

 by the late Sir H. de la Beche^ forming the type of the family. 

 All the genera were arranged by Sir P. Egerton under the Lepi- 

 doid family of the order Ganoidei, and Mons. Pictet^ placed them 

 in his second family of Ehombiferous Oanoids — the LepidosteidcB, 

 and under the second tribe of that family — the homocercal Lepi- 

 dosteidcB (Lepidoides Homocerqties, Ag.) , which he further subdivided 

 into sections, some of which included the above-mentioned genera — 

 viz.. 



Species having an elongated body, a short dorsal fin, fulcra in a 

 single row, dorsal chord persistent and protected by half- vertebra 

 (" halb-wirbel," Heckel.)— Semionotus, Pholidophorus. 



Species having the body elevated and compressed, a single dorsal 

 fin, one roio of fulcra, a persistent dorsal chord protected by partially 

 ossified vertebrae — Tetragonolepis, Dapedius, Amhlyurus. 



1 Palaaontology, 1861, 2nd Edit., p. 166. 



2 Geol. Trans., 2nd Series, Vol. i. pi. 6, fig. 1-4. 



3 Traite de Paleontologie, 2ud Edit., 1854, Vol. ii., p. 157. 



VOL. VI. — NO. LXII. 22 



