Title: The Canadian field-naturalist
Identifier: canadianfieldnat1932otta (find matches)
Year: 1932 (1930s)
Authors: Ottawa Field-Naturalists' Club
Subjects:
Publisher: Ottawa, Ottawa Field-Naturalists' Club
Contributing Library: Harvard University, Museum of Comparative Zoology, Ernst Mayr Library
Digitizing Sponsor: Harvard University, Museum of Comparative Zoology, Ernst Mayr Library

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132 The Canadian Field-Naturalist (VoL.fXLVI Plate II
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Figure 1 Inferior View About ^ Natural Size. Figure 2 Side View Less than J Natural Size. section except for a flattening on the inner side. The crown is divided from the fang by a well- defined neck or constriction and is laterally com- pressed. Though the crown is short and broad (fore and aft) it terminates in a sharp point. On the teeth immediately succeeding the canines the carinae are internal to the middle of the crown, but in the posterior teeth these ridges mark almost the centre of the anterior and posterior faces. The inner face of the crown is almost flat, whereas the outer face tapers from the broad base to the narrow tip thus giving the outer face of the crown a convex contour. In none of the teeth is the antero-posterior diameter of the crown greater than the height as shown by Gilmore for the posterior teeth of L. sternbergii, (loc. cit. p. 491). The following measurements give an idea of the relative proportions of the teeth, the first measure- ment represents the height and the second the antero-posterior diameter at the base of the crown taken in millimeters. Fourth premaxillary, 18-6; maxillary teeth, first 9-4; fourth 22, estimated-9; eighth 8-5.5; eleventh 9-6.5; fourteenth 9-6; eighteenth 5-4; twentieth 4-4; fourth dentary tooth 23-7.5. There is a very fine wrinkling of the enamel on most of the teeth behind the canines. It is best shown near the tips and on the posterior teeth. The first dentary tooth bites into a pit in the premaxilla and the third and fourth bite into a notch between the premaxilla and maxilla. The lower teeth alternate with the upper and bite within and between the maxillary teeth. External to, and in advance of, the fifteenth, sixteenth, and seventeenth teeth are moderate-sized but well defined pits into which maxillary teeth bite. This alternation of the teeth is well shown in PI. II, Fig. 2. The fourth tooth (the most advanced of the dentary series preserved) is very long, slender, inwardly curved, and rather sharply pointed. In the articulated head this tooth extends well above the top of the skull, (PI. II, Fig. 2, C). It is sub- circular in cross section but with a very slight flat- tening of the inner face in its distal half. The carinae, which are low but well defined, do not reach to the base of the crown and the crown is not sepa- rated from the fang. The third dentary tooth was similar, in size and shape, to the fourth, as shown by the alveolus. Germ teeth are present in the sixth and eighth alveoli of the left side while number seven carries a fully developed tooth.

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