The oral cirri of Siluroids and tlie uriinin of the lieail in Vertebrates. 421 



the lower jaw, than to the more modified Protopterus. Therefore the 

 resembhiuce may be due to convergence. Other features forbid entirely 

 the close alliance of Dinichthys and Protopterus. The latter has no 

 structures corresponding to the spines of the former. The whole 

 dermal armature is entirely different, and finally the distribution of 

 the lateral line system, as figured by Claypole, is in no respect like 

 that of Ceratodus or Protopterus (I have examined both of the latter 

 animals on this point), while it bears a remarkable similarity to that 

 of Clarias, as figured by me. 



Returning to Coccosteiis, I may state that I have examined a 

 number of specimens and the dermal armature certainly shows no 

 affinity with Dipnoi. Elsewhere I have endeavoured to prove that the 

 lateral line of Clarias closely resembles that of Coccosteus ., thus of- 

 fering confirmation of Huxley's view. 



The Siluroids are therefore not classed with the Cephalaspidae 

 and Coccosteidae mainly on negative evidence, such as the absence of 

 pectoral fins or clavicular bones and the absence of internal ossi- 

 fication. 



Owens College Manchester 

 Dec. 1894. 



Bibliography. 



Büchner, G., Mémoire sur le système nerveux du Barbeau, Strasbourg 



183t;. 

 Claypole, E. W., On the structure of the American Pteraspidian, Palae- 



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 — The head of Diiiichthys, in: Amer. Geologist, V. 10, 1892. 

 CuviKR, Mémoire sur la composition de la mâchoire supérieure des 



poissons, 1814. 

 [Dean, Bashford, The pineal fontanelle of Placodermata and Catfish, 



in: Rep. of Fish Comm. 19, New York.] 

 FCtrbbixoer, Paul, Unters, z. vergl. Anat. d. Musk. d. Kopfskelets d. 



Cyclostomen, in: Jena. Zeitschr., V. 9. 

 Gauit, Primordialcranium von Rana fusca, in: Morph. Arb. Schwalbe, 



V. 2. 

 Geoenbal'r, C, Ueber die Kopfnerven von Hexanchus, in : Jena. Zeitsch., 



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