Cope.l °v^ [March 7, 



The statement "maxillary wanting," is in contradiction to the definition 

 of the sub-class Hyopomata, which asserts the presence of those bones. 

 Stannius* has asserted the absence of the "oberkiefer" in the eel; 

 Giintherf describes their presence. As the absence of the maxillary bone 

 would constitute a point of resemblance, if not affinity to the Elasmo- 

 branchi, I have reexamined my material to determine the homologies of 

 the lateral dentigerous bone of the upper jaw of the eels. My specimens 

 of species of the Colocephali include the following from theHyrtl collec- 

 tion : Myrus vulgaris ; Sphagebranchus rostratus ; Moringua rcetaborua ; 

 Murcena sp.; Murmna unicolor ; Murmna sp.; Poecilophis polyzonus, 

 and Gymiiomurazna tigrina. The pterygoid bone exists in a rudimeDtal 

 condition in the Gymnomurama tigrina, Myrus vulgaris, and one of the 

 species of Muraena ; and whether lost in the preparation of the other crania 

 or not, cannot be stated. In the Anguilla vulgaris the pterygoid bone is con- 

 siderably larger, and extends to a point halfway between its base and the 

 extremity of the muzzle. In the Conger vulgaris it extends still further 

 forwards, reaching a transverse process of the anterior part of the vomer. 

 No palatine bone appears. The premaxillary bone is not distinguished 

 from the ethmoid in the Colocephali, nor in the Enchelycephali (Anguil- 

 lidse, etc.). It is quite possible, therefore, that the external dentigerous 

 bone or upper jaw, in both of these orders, may be the palatine, and the 

 maxillary be wanting. The family of the Mormyridae appears to furnish 

 the solution. In this group the structure and connections of the pterygoid 

 bone are much as in Conger, and there are in addition distinct premaxillary 

 and maxillary bones. It is clear that in this family it is the palatine, and 

 not the maxillary bone, that is wanting. Similar evidence is furnished 

 by the family Monopteridse. The definition of all four of the orders, 

 Colocephali, Enchelycephali, Ichthyocephali and Scyphophori must, 

 therefore, embrace this character. The Gymnarchidse agrees with the 

 Mormyridae in this respect, and both families have the transverse process 

 of the vomer which receives the pterygoid, as in the genus Conger.:]: The 

 supposed resemblance to the sharks presented by the Colocephali is then 

 not real, and the question as to the point of affinity of the Ichthyotomi to 

 the true fishes remains open as before. 



I now refer to the remarkable characters presented by the deep sea fishes 

 of the family Eurypharyngidse, as recently published by Messrs. Gill and 

 Kyder.§ These authors find the characters of the skeleton so remarkable, 

 that they think it necessary to establish a new order for its reception, 

 which they call the Lyomeri. The definition which they give is the fol- 

 lowing : "Fishes with five branchial arches (none modified as branchi- 

 ostegal or pharyngeal) far behind the skull ; an imperfectly ossified skull 

 articulating with the first vertebra by a basioccipital condyle alone ; only 



* Handbuch der Zootomie, Fische 1854, p. 76. 



f Catalogue Fishes,'British Museum, vol. viii, p. 19. 



% These transverse processes are enormously developed in Gymnarchus. 



§ Proceedings TJ. S. National Museum, Nov. 1883, p. 262. 



