162 MARINE PRODUCTS OF COMMERCE 



common Atlantic herring, Clupea harengus, already referred to several times 

 in these pages as a common type of fish, has teeth in its jaws when young, but 

 loses them or retains only minute ones when full grown. A related herring, the 

 common shad, Alosa sapidissima, entirely loses its teeth as it attains the adult 

 stage. However, the jaw teeth in the herring family, Clupeidae, are not always 

 lost with age. Indeed, in the small tropical species, Chirocentrodon bleekeriana, 

 the teeth become larger and even fanglike. 



In some fishes, such as spadefish, mullets, and others, small or weak cardiform 

 teeth persist. At the other extreme are the triggerfish which have large incisor-like 

 teeth. A specimen of the triggerfish, Balistes naufragium, 22 inches long, taken 

 near Balboa, Canal Zone, has incisors not unlike those of a grown man in size and 

 shape. Through a painful experience the writer learned that a triggerfish can use 

 its teeth very effectively for cutting. Barracudas, bluefish, etc., have large com- 

 pressed pointed teeth, whereas the cutlass fish have large, somewhat curved and 

 compressed teeth. The parrot fish have still another type, a sort of beak com- 

 posed of small teeth fused to form a continuous cutting edge. 



Sharks, skates and rays, and chimaeras, that is, the cartilaginous fishes, in gen- 

 eral have teeth that differ from those of the bony fishes. As a rule they are more 

 formidable, though variable in size. Unlike those of the bony fishes they are set 

 in the gums instead of in the bone. The teeth of sharks commonly have a broad 

 flat triangular cusp, often flanked at the base by one or more small cusps, the 

 cutting edges of which are usually serrated. These teeth occur in several series. 

 When the anterior or functional series wear out, the teeth are shed and replaced 

 by the next row. This is true of the teeth in the man-eater, Carcharodon carcharias, 

 and the tiger shark, Galeocerdo arcticus, both dangerous to man. However, all 

 sharks do not have large teeth. In fact, the two largest species of living sharks, 

 the giant whale shark, Rhincodon ti/pus, and the huge basking shark, Cetorhinns 

 maximus, have very small teeth and feed on nothing larger than perhaps a fish 

 a few inches long. 



The teeth in many skates and rays are very different from those of the sharks, 

 as they often are flat and arranged like bricks in a pavement. Such teeth occur 

 in the giant eagleray, Aetobatis narinari, sea devils, Manta, sawfish, Pristes, and 

 many other skates and rays. The chimaeras or elephant fish, too, have teeth with 

 flat surfaces. 



Many fishes, in addition to having teeth in the jaws, also have them on the 

 bones of the roof of the mouth, that is, on the vomer, palatines, and pterygoids; 

 some are even located on the tongue and hyoid bone. Once more using the 

 Atlantic herring, Clupea harengus, as an example, we find teeth on its vomer, 

 palatines, and tongue. Indeed, it is the only member of its family on the Atlantic 

 Coast of the United States and Canada that has teeth on the vomer; by this 

 character alone it may be identified within its range on the American Coast. 



Some fish have teeth on the pharyngeal bones, which are situated far back in 

 the mouth. The members of the very large family, Cyprinidae, of fresh- water 

 fishes, including carps and hundreds of species of minnows of the shiner type, 

 have such teeth. The pharyngeal teeth in minnows are generally more or less 

 pointed and often hooked. However, those of the black drum, Pogonias cromis, 

 constitute an outstanding example of highly specialized pharyngeal teeth; they 

 are low and flat and form, together with the bones in which they are set, a dental 



