232 PISCES. 



bony projections, which arise from the bottom of the dental socket ; 

 this is the case with the incisor teeth of Balistes, that thus present a 

 double gomphosis. There is frequently a slight anchylosis of the 

 bases of the teeth to the walls of the alveolar cavity, as in Sphy- 

 raena, Acanthurus, and others. In the majority of cases an actual 

 fusion of the bony substance of the jaws with the sockets of the 

 teeth exists. Before, however, this anchylosis is completed, the 

 tooth has been united to the jaw by ligament. Occasionally, as in 

 the posterior teeth of Lophius, the teeth are fastened by elastic liga- 

 ments to the maxillae, and so disposed that during deglutition they 

 yield downward and backward so as to offer no obstruction to the 

 passage of food, and again spring up into their usual erect position 

 when the pressure is removed. The teeth of the Sharks, for the 

 most part bifurcated inferiorly, are attached by ligaments to the partly 

 ossified edges of the maxillae. A very curious mode of attachment 

 is exemplified by the teeth of the Eagle-Ray (Myliobatis), in which 

 the flat hexagonal teeth are united by suture to a series of quadrangu- 

 lar pieces. 



The form of the teeth is likewise very varied, being either conical 

 as in most Fishes, flat, prismatic, or cylindrical. The conical kind 

 are frequently very numerous, and in such cases so small as to ap- 

 pear like papillae, and may possibly serve only as instruments of 

 touch ; in other instances they are longer, almost filamentary like 

 bristles, and divided at their apex into two or three prongs ; in many 

 Fish, e. g., in Trichiurus, they are provided at their points with 

 hooks ; they are frequently largely developed, for instance, the ca- 

 nine teeth of many Carnivorous Fishes, e. g., the Sea- wolf (Anar- 

 rhicas Lupus). The incisor teeth also may be perfectly flattened 

 like those of the human subject, as in Sparus sargus, L., and behind 

 these stand short cylindrical teeth with rounded flattened crowns. 

 Such flattened teeth differ both in form and size ; their plates are 

 cylindrical, elliptical, elongated, triangular or quadrangular, semilunar 

 or falciform ; the same flat, tessellated kind of teeth are found in the 

 jaws of the Saw-fish. It is not rare for the teeth upon the two 

 jaws to differ, as in the Sharks, where the teeth that are destined 

 to rise up and replace the others when they fall out, form numerous 

 rows lying like tiles one over the other upon the inner walls of the 

 maxillae. 



The number of the teeth ranges from one to so many that they 

 can be scarcely counted. Thus the Myxinoidae (e. g., Bdellostoma, 

 Myxine) have only one single slightly-curved tooth on the palate. 



