2 ±6 MESSRS. HANCOCK AND HOWSE 



enable him to describe it fully, yet in the foregoing description 

 we find a sufficient number of characters to justify us in referring 

 our specimens to this peculiar fish. Among these the position 

 of the lower jaw, the rather large orbit, and the unusually long 

 dorsal fin would alone be sufficient to establish this identity; but 

 to these points may be added the situation of the pectoral in the 

 mid-height of the body, the curious "ribbon-shaped" process 

 descending from behind the pectoral to the ventral margin, the 

 abdominal rod which bounds the ventral cavity behind (not men- 

 tioned by Germar or Munster, but characteristically shown in 

 their figures) the hourglass-shaped processes beneath the dorsal, 

 and the peculiar sigmoidal plates seen near the ventral margins 

 of the posterior half of the body : these establish beyond any 

 doubt, not only the generic, but also the specific identity of the 

 Marl-slate with the Kupferschiefer specimens. But there are a 

 few points in Prof. G-ermar's description which the more perfect 

 state of the specimens we have had the use of enable us to cor- 

 rect. It will appear in the sequel that what seemed to Grermar 

 to be an internal bony skeleton is, according to our observations 

 and opinions, also in part an exo-skeleton. The situation of the 

 ventral fin also, which is placed in this fish under the throat and 

 rather in advance of the pectoral fin and ventral cavity, has been 

 overlooked by this author (for, judging from his figure, the vent- 

 ral appears to be present) ; and in consequence of this oversight 

 he has been led to describe the anal as the ventral, and the anal 

 (which is well shown in his specimen) as not present. Another 

 point deserving of remark is the statement that the tail is homo- 

 cereal. This mistake arose, no doubt, from the imperfect state 

 of the tail in the specimen examined ; but in those which we 

 have investigated this fin is very well preserved in three indivi- 

 duals, and shows itself to be decidedly heterocercal. The size 

 of Germar' s specimen is rather less than that of three of ours ; 

 but the dorsal fin is more perfect and more characteristically 

 shown in the German than in those which we have before us 

 from Midderidge. 



Count Munster says of his Platysomus Althausii (Munster, 

 Beitrage, Heft v., p. 44, tab. v., f. 2) that "the only two small 



