LUCIOIDS. 131 



the whole, relatively larger than in the Sphyrcenodus, and are more 

 flexuous in their course ; and the spaces intercepted by their anasto- 

 moses are less angular. These spaces (b) exhibit every where 

 plexiform groups of flexuous calcigerous tubes proceeding from the 

 medullary canals. The clear and dense investment of the tooth 

 presents the same structure as the peripheral dentine in other Scom- 

 beroid fishes, being traversed by sub-parallel and acutely-branched 

 calcigerous tubes, passing from the nearest medullary tubes, at right 

 angles to the surface of the tooth, and diminishing to extreme tenuity 

 in the clear outer portion of the investing layer, c. No Saurian tooth 

 recent or extinct has presented the type of structure here described : 

 the distribution of branched and reticularly anastomosing medullary 

 or pulp-canals through the whole body of the tooth is a peculiarly 

 Ichthyic condition of the dental structure ; and the modifications of 

 this condition presented by the tooth of the Saurocephalus, are most 

 closely aUied to those which characterize the teeth of the Scomberoid 

 Fishes. 



In Plate 55 an entire tooth of the Saurocephalus lanciformis and 

 a portion of jaw, containing two others imbedded in their sockets, 

 are represented of the natural size, by the side of the magnified sec- 

 tion. The small foramen opposite the fang of each tooth is described 

 by Dr. Hay, as being for the transmission of nerves and blood-vessels 

 to the teeth. I have httle doubt, from the analogy of the Sphyraena, 

 that these foramina lead to the cavities containing the germs of the 

 successional teeth. They are placed as in the Sphyraena, on the inner 

 side of the alveolar process. 



LUCIOIDS. 



53. The fishes of the family typified by the voracious Pike, and 

 hence termed ' Lucioids,' have a more complicated dentition than those 

 of the preceding family ; but the teeth are characterized by a similar 

 reticulo-medullary tabular structure, distinguished chiefly by the 

 more regular size and form of the meshes or interspaces of the anas- 

 tomostic net-work. 



The Scomberesox is a genus which connects the Scomberoid with 

 the Lucioid family of fishes. The jaws of a species of this genus from 



K 2 



