VOL. LXXIV.] PHILOSOPHICAL TRANSACTIONS. 541 



The external row consists of 3 or 4 sharp or conical teeth; and the internal row 

 of 4 or 5 blunt and rather flat ones. These bones are connected to the palate 

 and bones of the nose by loose but strong ligaments. The 3d bone of the upper 

 jaw, which may be called the anterior or nasal portion, is of a triangular form, 

 connected above to the bones of the nose, and ending below in a flat surface, 

 thick-set with sharp conical teeth. The external teeth, about 4 in number, are 

 large and strong, and bend a little inwards; but the internal ones are small, and 

 nearly straight, of which we may reckon about 10. 



The lower jaw d, consists of 2 bones, united at their fore-parts by a strong 

 ligament, which allows of some motion. On their anterior extremities are placed 

 6 large and as many small sharp and conical teeth; the large teeth are placed 

 externally, and their points are bent a little inwards; while the small ones, which 

 stand within them, are nearly straight. Behind these are 2 or 3 rows of grinder 

 teeth. The external teeth stand nearly upright; but the internal ones are placed 

 obliquely, inclining towards each other. The teeth are formed of a hard bony 

 matter, not covered with enamel as in some animals; nor is there an equal dis- 

 tribution of enamel and bone as in some others. They are not fixed in sockets, 

 but are fastened to the jaws in the same manner as the epiphyses are united to 

 the bodies of the bones in young animals. 



From the foregoing description it will appear, that the anterior sharp teeth of 

 the sea wolf are admirably calculated for seizing its prey, while the posterior 

 grinding teeth serve to break down the hard shells of lobsters, crabs, muscles, 

 scollops, &c. which this animal is known to feed on. The external teeth on the 

 sides of the upper and lower jaw being higher than those placed within them, a 

 hollow is formed above and below, in which the convex shells of crustaceous 

 animals, &c. are confined during their compression between the jaws, which is 

 effected by the action of strong muscles placed on the sides of the head. The 

 jaws being made up of a number of pieces, and connected by loose ligaments, 

 a freedom of motion is allowed, and the collision or shock arising from the com- 

 minution of hard bodies is so much the less by being divided among a number 

 (T bones. 



Of the chcelodon nigricans. — The individual which furnished the following ac- 

 count was brought from the West Indies, and measured about 5 inches in length.* 

 Its teeth were so small as to require the assistance of a microscope to discover 

 their real shape. There were 14 in each jaw. They consist of a cylindrical body- 

 fixed in the jaw, above which they spread out into a broad and rather flat surface, 

 on the edges of which are 12 or 13 denticuli, making an uncommon appearance, 

 and totally different from the teeth of any other animal. Another singularity is 



* This fish is well represented in Du Hainel Traite general des Peschees, torn. 3, seconde partie, 

 section 4, planche 12, under the name of Chiiurgien ou porte lansette. — Orig. 



