Jaws and Teeth

jaw, lower, figure, tooth and found

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Louis Agassiz (1843) not only figures the jaws and teeth of S. barra cuda but the skull and skeleton as well. His beautiful figure, which in the main points is technically correct, is herein reproduced as figure 21, plate vi, while figure 22, plate vi, is an enlarged photographic copy of the skull and adjacent parts. The one point criticizable is that the pelvic fin is possibly placed slightly too far forwards. After noting that all the parts of the head are much elongated Agassiz says: "The intermaxillaries have a single row of small teeth on their lateral border, but in front and a little inside there are two very large ones, compressed and very trenchant, slightly bowed and very pointed, accompanied sometimes by one or by two teeth much smaller. Farther back and on the same line, the palatines bear a series of five or six equally large, sharp and pointed teeth, not bent but for the most part like lance heads. Succeeding also to these on the length of the palatines are twelve or fifteen teeth much smaller and serrated like those on the intermaxil aries. The lower jaw has only two large trenchant teeth, pointed and bent, at the anterior symphysis of the branches of the mandible, which correspond to those of the upper jaw. Along each arm of the lower jaw, there follows each other a series of teeth, trenchant, straight, pyramidal in appearance, more or less large and more or less elon gated. These correspond to the grand palatines and fit in between these and the intermaxillaries when the animal closes its formidable mouth." To recapitulate, Rondelet (1558) and Salviani (1554) each found a single tooth at the symphysis of the branches of the lower jaw; so did Sloane (1725) and Catesby (1754) and Parra (1787), while Biittikofer (1890) found but one in the lower jaw of S. jello caught off the coast of Liberia. Jordan and Evermann (1896) call for and figure but one. Fowler (1903) found but one in S. tome. Bullen (1904), in his very spirited figure (text-figure 1), shows but one fang. Wood-Jones (1912), in his photograph (figure 2, plate I) of a giant specimen from Cocos Keeling Islands, shows but one tooth. My five specimens, as their photographs show, had but one fang each. On the other hand Browne (1756) speaks of two teeth at the symphysis of the lower jaw as does Guichenot in his "Poisson de Cuba" (1850). In describing the spet of Mediterranean waters, Cuvier and Valenciennes (1829) distinctly say that at the point of the lower jaw are two large, strong, curved teeth. Of the great barracuda they say that the dentition is like that

of the spet. Their full-length figure of S. barracuda shows but a single tooth at the apex of the lower jaw, but their line drawing of the head found on the same plate shows two straight fine-pointed teeth. The single tooth in the other figure is, however, correctly hooked backward. Agassiz (1843) likewise says that the lower jaw has two great teeth at its apex, but his figure shows only one. (See figure 22, plate vi.) The last to be quoted is Day (1865), who says that there are two large canines in the anterior part of the lower jaw of S. jello of India.

It is interesting just here to note that Cuvier and Valenciennes quote Plee as saying that he has seen great numbers of young barra cudas not more than 6 inches long and that "all lack the tooth of the lower jaw." The following data, however, may be given for specimens hardly more than one-third as long as Plee's. The four little barra cudas taken at Tortugas in 1917, and described on page 59 for their color markings, have the great tooth of the lower jaw present and exposed for study by reason of the shrinking of the tissues at the tip of the upper jaw. The largest and bulkiest fish (2.6 inches long to the base of the caudal) has but one lower anterior tooth, the right. All three of the others (measuring 2.6, 2.35, and 2.25 inches) have but one each and that the left tooth.

After thinking on the matter for some time, it became clear to me that since the lower jaw is bilateral and since there is one fang at the external end of one ramus of the mandible, there is due to be one at the other. When the head of the fresh specimen from Miami was cleaned off, there (in the proper position), was the base of the broken-off left fang. A little dissection of the largest dried head revealed a pre cisely similar state of affairs. Removal of a lot of tissue at the apex of the lower jaw of dried specimen No. III showed a new tooth nearly ready to break through; and in the smallest dried head the stump of a broken-off tooth was found.

From a consideration of the foregoing facts it is clear that the great barracuda normally has two great teeth at the apex of the lower jaw, but for some unknown reason only one is commonly found, the one or the other being broken off. It would be of no small interest if the reason for this could be ascertained.

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