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ON SCLERORHYNCHUS ATAVUS. 



[Nov. 19, 



The broad median cartilage is distinct, very robust, displaying the 

 numerous well-calcified tesserae ; and on either side of this the 

 narrow area is comparatively thin, though exhibiting small tesserae 

 that are more suggestive of cartilage-calcifications than of shagreen- 

 graiuiles. The anterior extremity of the type specimen (Catal. Foss. 

 Fishes B. M. pt. i. pi. iii. fig. 1) shows a single pair of broad 



Kostrum of Sclcrorhijnchus atavus. 



lateral cartilages occupying the entire width of the snout outside the 

 median rostral cartilage ; and it seems probable that a similar 

 arrangement exists in the new specimen now exhibited. A few rostral 

 teeth occur, of the form already described in the British Museum 

 Catalogue. 



*' A third head and rostrum of Sclerorhynclius has lately been 

 detected, mingled with remains of Teleostean fishes, upon a small 

 slab from Mt. Lebanon in the British Museum (no. .53663). Though 

 very imperfectly preserved, this fossil confirms the observations 

 made upon the previous specimens, and also makes knowtt the form 

 and proportions of the teeth in the mouth. These teeth are remark- 

 ably similar to those of a Lebanon fish of which the hinder portion 



