164 ON THE MORPHOLOGICAL CONSTITUTION OF 



like portion of the basis of the cranium. In most fishes there 

 will be found in this membrane, where it passes off from the 

 pre-sphenoidal portion of the cranium, a more or less elongated 

 scale-like bone on each side. This is the " pterygo'idien 

 interne" of Cuvier, the "herisseal" of St. Hilaire, the "ento- 

 pterygoid" of Professor Owen. The palate-bone, connected 

 by the same fibrous membrane to the outer margin of the 

 ento-pterygoid, extends forwards to the side of the so-called 

 " vomer," or to the ethmoidal centrum and neurapophysis, to 

 which, as also to the maxillary and intermaxillary, it is 

 variously attached directly and indirectly. The corresponding 

 actinapophyseal element or pterygoid in the fish is firmly 

 connected in front to the palate-bone, and less intimately to 

 the ento-pterygoid, and, extending backwards, downwards, and 

 outwards, abuts against the anterior margin of the " hypo- 

 tympanic " and " pre-tympanic " bones, as the pterygoid of the 

 bird and reptile does against the so-called "quadrate," or 

 " tympanic " bone. If, then, the basal aspect of the cranium 

 of the osseous fish is placed in series with those of the bird, 

 lizard, serpent, tortoise, and frog, it will be observed, that 

 while its palatals and pterygoids may be at once associated 

 with the corresponding bones, as already determined, in the 

 bird and reptile, the ento-pterygoid of the fish presents all 

 the relation of the double bone, usually called " vomer " in the 

 bird ; of the posterior or horizontal portion of the bone called 

 " vomer " in the tortoise ; and of the bones called " palatals " 

 in the lizard, serpent, and frog. It will also be observed, that 

 while the toothed bone, called " vomer " in the fish, has, from 

 a catacentric change, disappeared from the under aspect of the 

 cranium in the bird, reptile, and batrachian, the two bones, 

 called in the fish " pre-frontals " its ethmoidal neurapophyses 

 present the same relations to its ento-pterygoids as the 

 ethmoidal neurapophyses of the bird to its so called " vomer," 

 and as those of the tortoise to the posterior portion of its so- 



