DEPOSITS OF ORANGE FREE STATE, SOUTH AFRICA. 143 



in the mode of articulation of the scales. Tetragonolepis (Bronii, 

 non Agassiz *), on the other hand, has a truly " pleurolepidal " 

 squamation, the inner articulating ribs of the scales being anterior 

 and marginal. But the typical species of this genus are much less 

 symmetrically shaped than the South-African form, owing to the 

 great development of the ventral part of the abdominal region ; 

 though, it must be admitted, at least one of the fragmentary Indian 

 fossils referred by Egertonf to Tetnujonolepis exhibits an almost cor- 

 responding general outline, so far as it is known. Whether the latter 

 is a correct determination or not remains to be decided by the dis- 

 covery of more satisfactory materials ; but, under any circumstances, 

 it is obvious that the fish now under discussion is quite distinct from 

 the type defined by Broun J, and must therefore be looked upon as 

 representing a different genus. At first sight I was inclined to regard 

 it as new, but Dr. Traquair has kindly reminded me of a fish from the 

 Hawkesbury Beds (supposed Trias) of New South Wales, described 

 many years ago by Sir Philip Egerton § under the name of Cleiihro- 

 lepis granulatus, and I am convinced that the South- African fossil 

 is generically identical with this. CleiiJirolepis, up to the present 

 time, has been doubtfully placed either with the Platysomidse or the 

 Pycnodontidae, but Sir Philip Egerton's figures and description 

 clearly show that its true affinities are with the family Dapediidse ; 

 and the new discoveries here recorded amply confirm this determi- 

 nation. The South-African fish, however, is distinctly a new spe- 

 cific type, as will be seen on comparing the figures, and I therefore 

 venture to name it Cleithrolepis Exioni, in reference to Dr. Exton's 

 important explorations in the early Mesozoic deposits of the Cape. 



Formation and Locality. — Stormberg Beds (Upper Karoo Series) : 

 Rouxville, Orange Eree State, South xifrica. 



EXPLANATION OF PLATE VI. 



Fig. 1. Semionotus capensis, A. S. Woodw., hinder portion of trunk. 



2. Ditto, head and pectoral fin. cl, clayicle ; co, coracoid ; d, dentary ; 



//', frontal ; op, operculum ; or^,orbit ; par, parietal ; p.op, preoper- 

 culum ; s.op, suboperculum ; st, supratemporal ; x, cheek-plate. 



3. Ditto, caudal pedicle and fin. 



4. Ditto, scale of flank, inner aspect, twice nat. size. 



5. Ditto, ventral scale, inner aspect, twice nat. size. 



6. Cleithrolepis Exfoni, A. S. Woodw. 



7. Ditto, fragment of head and trunk, with pectoral fin. 



All the figures, except Nos. 4 and 5, are of the natural size, and the original 

 specimens are preserved in the British Museum. 



(For the Discussion on this paper, see p. 269.) 



* See Sir Philip Egerton, "On the Affinities of the Genera Tetragonolepis 

 and Dapedius," Quart. Journ. Geol. Soc. vol. ix. (1853), pp. 274-277. In this 

 paper Tetragonolepis was assigned to the Pycnodontidse, but the error has sub- 

 sequently been pointed out by both Heckel (Denkschr. k. Akad. Wiss. Wien, 

 vol. xvii. 1855, p. 200) and Traquair {loc. cit. p. 380). 



t Sir P. Egerton "On some Remains of Ganoid Fishes from the Deccan," 

 Palaont. Ind. [4] vol. i. pt. 2 (1878), p. 5, pi. iii. fig. 1. — Tetragonolepia analk. Eg. 



\ H. G. Bronn, " Ueber zwei fossile Fischarten aus dem Gryphitenkalke bei 

 Donau-Eschiugen," Neues Jahrb. 1830, p. 22, pi. i. fig. 2. 



§ Sir P. Egerton, " On some Ichthyolites from New South Wales, forwarded 

 by the Rev. W. B. Clarke," Quart. Journ. Geol. Soc. vol. xx. (18G4), p. 3, pi. i. 

 figs. 2, 3. 



