SCOMBEROIDS. 127 



but smaller. The palatine bones contain each nine or ten lancet 

 shaped teeth, somewhat larger than the posterior ones of the lower 

 jaw. All these teeth afford good examples of the mode of attach- 

 ment by implantation in sockets, which has been denied to exist in 

 fishes. (1) 



The loss or injury to which these destructive weapons are liable 

 in the conflicts which the sphyrsena wages with its living and strug- 

 gling prey, is repaired by an uninterrupted succession of new pulps 

 and teeth. The existence of these is indicated by the foramina, (2) 

 which are situated immediately posterior to, or on the inner margin of 

 the sockets of the teeth in place ; these foramina lead to alveoli of 

 reserve, in which the crowns of the new teeth in different stages of 

 development are loosely imbedded. It is in this position of the 

 germs of the teeth that the Sphyraenoid fishes, both recent and fossil, 

 mainly differ as to their dental characters from the rest of the Scom- 

 beroid family, and proportionally approach the Sauroid type. The 

 base or fang of the fully- developed tooth of the Sphyrsena is an- 

 chylosed to the parietes of the socket in which it is inserted. The 

 pressure of the crown of the new tooth excites absorption of the 

 inner side of the base of the old, which thus finally loses the requisite 

 strength of attachment, and its loss is followed by the absorption of 

 the old socket, as in the higher animals. 



It is interesting to observe that the alternate teeth are, in general, 

 contemporaneously shed ; so that the maxillary series is always pre- 

 served in an effective state. The relative position of the new teeth to 

 their predecessors, and their influence upon them, resemble, in the 

 Sphyrsena, some of the phenomena which will be described in the 

 dentition of the CrocodiHan reptiles. To the crocodiles the present 

 voracious fish also approximates in the alveolar lodgment of the teeth, 

 but it manifests its ichthyic character in the anchylosis of the fully 

 developed teeth to their sockets, and still more strikingly in the 

 intimate structure of the teeth. 



Few microscopic objects are more beautiful than a longitudinal 

 and transparent section of the tooth of the Sphyra?na, which accurately 



(1) Cuvier, Histoire Naturelle des Poissons, torn, i, p. 492. 



(2) PI. 53, fig. 1, a, a. 



