TEETH OF THE BARRACUDA FISH. 249 



and serial teetli gradually increase in size towards tlie 

 back part of the jaw ; there are about twenty -four of these 

 piercing and cutting teeth in each premandibular bone. 

 They are opposed to a double row of similar teeth in the 

 upper-jaw, and fit into the interspace of these two rows 

 when the mouth is closed. The outermost row is situated 

 on the intermaxillary, the innermost on the palatine 

 bones ; there are no teeth on the vomer or superior max- 

 illary bones. The two anterior teeth in each premax- 

 illary bone equal the opposite pair in the lower-jaw in 

 size ; the posterior teeth are serial, numerous, and of small 

 size ; the second of the two anterior large premaxillary 

 teeth is placed on the inner side of the commencement of 

 the row of small teeth, and is a little inclined backwards. 

 The retaining power of all the large anterior teeth is in- 

 creased by a slight posterior projection, similar to the barb 

 of a fish-hook, 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 

 afibrd good examples of the mode of attachment by im- 

 plantation in sockets, which has been denied to exist in 

 fishes. 



The loss or injury to which these destructive weapons 

 are liable, in the conflict which the sphyrsena wages with 

 its living and struggling prey, is repaired by an uninter- 

 rupted succession of new pulps and teeth. The existence 

 of these is indicated by the foramina, 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 croAvns of the new teeth in dif- 

 ferent stages of development are loosely imbedded. It is 

 in this position of the germs of the teeth that the sphyrae- 

 noid fishes, both recent and fossil, mainly differ, as to their 



