. Animal Life and the World of Nature; A magazine of Natural History. Pharyngeal Teeth of the Carp. In addition, there are the Tench and the Carp, which subsist very largely upon water- plants, having the most powerful pharyngeal teeth. In the carp these teeth (Fig. 15) are arranged in two or three rows, the innermost row including a single tooth, the second having in some cases two rather larger ones, while those of the third row are the largest and most complex of all. In these the front one is the largest and has a smooth crown; the crowns of the others, when unworn, being sculptured. The l
. Animal Life and the World of Nature; A magazine of Natural History. Pharyngeal Teeth of the Carp. In addition, there are the Tench and the Carp, which subsist very largely upon water- plants, having the most powerful pharyngeal teeth. In the carp these teeth (Fig. 15) are arranged in two or three rows, the innermost row including a single tooth, the second having in some cases two rather larger ones, while those of the third row are the largest and most complex of all. In these the front one is the largest and has a smooth crown; the crowns of the others, when unworn, being sculptured. The last type of fish dentition to which I have space to allude is adapted to a purely carnivorous diet, and is presented by those voracious fishes known as Barracuda-Pikes (Sphyrcena), which are relatives of the mackerel and the thunny. In one of the largest species the lower jaw (Fig. 16) is armed with a formidable array of sharp, lancet-like teeth, arranged in a single series, there being about twenty-four of these in each side of the jaw, and their size gradually increasing from back to front. In the upper jaw they are opposed by a double series of similar teeth, into the interspace of which they fit when the mouth is closed. also nine or ten lancet-shaped teeth on the palate which present the peculiarity, rare imong fishes, of being implanted in separate sockets. As a rule the alternating teeth are shed, so that the formidable dentary apparatus is always maintained in a thoroughly efficient condition. Teeth of extinct barracuda-pikes are met with in the Tertiary deposits of Europe; but the antecedent Cretaceous seas must have absolutely swarmed with huge fishes armed with teeth more or less closely resembling those of the barracudas, and frequently inserted in distinct sockets. When the so-called coprolites of the Cambridge Greensand were worked for artificial manure, no vertebrate remains were more common in the phosphate heaps than the spear-like teeth of the fish then known
Size: 2885px × 866px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublisherlondo, bookyear1902
