BRITISH FOSSILS. 



Decade YI. Plate YIII. 



LEPTOLEPIS MACROPTHALMUS. 



[Genus LEPTOLEPIS. Agassiz. (Sub-kingdom Vertebrata. Class Pisces. Order 

 Goniolepidoti. Family Sauroidei. Sub-family Sauroidei homocerci. 1st Group. Tail 

 forked.) Scales very thin and rounded ; dorsal fin opposed to the ventrals ; operculum 

 broad ; sub-operculum large ; teeth villiform ; lower maxillaries with strong coronoid 

 processes.] 



STNOi^YM.—Leptolepis macropthalmuSy Egerton, Journal of Geol. Soc, 

 vol. i. p. 231. 



Generic Description. — In the year 1844, I communicated to the 

 Geological Society a brief account of this and some other fossil fishes 

 then recently discovered in the Oxford clay, at Christian Malford ; 

 but as no figure of this species is given in the Journal of that Society, 

 and as I have since had the advantage of examining a larger number 

 of specimens from the same locality, disclosing additional characters, 

 I have thought it an appropriate subject for this decade. Before 

 commencing the description of the species, I must allude to some 

 anatomical details common to the genus, which have induced me to 

 make some alterations in the generic characters assigned to it by 

 Agassiz. He describes (Poiss. Foss., vol. ii. p. 13.) the teeth to be 

 " en brosse, en avant des machoires ; de plus grosses dans leur 

 partie postdrieure and at part 2, p. 129, " lis ont des machoires 

 armies de dents coniques, absolument comme les Sauroides.'' After 

 a carefiil examination of more than 100 specimens in my own 

 cabinet, I have entirely failed to detect any trace of the conical 

 teeth alluded to in the foregoing quotation. I am, consequently, 

 inclined to believe that the teeth in this genus were exceedingly 

 minute, so much so as to have perished in most cases with the in- 

 tegumentary investment of the jaws. The only allusion to the teeth 

 in the specific descriptions of the Leptolepides in the " Poiss. Foss." is 

 to this effect : " Les dents ne sont visibles qu a la machoire inferieure ; 

 mais elles sont si petites, que ce sont presque des dents en brosse." 

 This entirely coincides with the result of my own examination, and 

 [vi. viii.] 6 I 



