. The Canadian field-naturalist. Natural history. THE OTTAWA NATURALIST Vol. XXI. OTTAWA, MAY, 1907 No. 2 NOTE ON THE OCCURRENXE OF A SUPERNUMERARY TOOTH IN A DOG.* By Lawren'ce M. , , , Geological Survey of Canada. Last summer whilst engaged in field work in the vicmity of Kamloops Lake, , the writer found, near the mouth of Tranquille River, the skull of a dog, probably that of a collie, that is of some interest. In this skull the teeth of the mandible appear to be normal, but in the upper jaw a supernumerary first premolar is present on both I Natural size Be
. The Canadian field-naturalist. Natural history. THE OTTAWA NATURALIST Vol. XXI. OTTAWA, MAY, 1907 No. 2 NOTE ON THE OCCURRENXE OF A SUPERNUMERARY TOOTH IN A DOG.* By Lawren'ce M. , , , Geological Survey of Canada. Last summer whilst engaged in field work in the vicmity of Kamloops Lake, , the writer found, near the mouth of Tranquille River, the skull of a dog, probably that of a collie, that is of some interest. In this skull the teeth of the mandible appear to be normal, but in the upper jaw a supernumerary first premolar is present on both I Natural size Between the second premolar and the canine (see the above figure) are two small, single-rooted teeth with simple conical crowns. Of these the one next behind the canine, and separated from it by a space measuring mm., is apparently the normal first premolar. Between this tooth and the second premolar is the tooth considered to be the supernumerary one. It is slightly smaller than the first premolar, and its posterior edge is less sloping; in other words, its crown, in side view, is more bilaterally symmetrical, a point possibly not sufficiently accentuated in the figure. It almost entirely occupies the interval between the first and second premolar, touching the latter but leaving a very narrow space between it and the former. The other teeth in the upper jaw, including the incisors, are apparently quite normal. In comparison with the skull of a white wolf (Canis lupus occidentalis var. alhtis) from Fullerton, Hudson Bay, the Tranquille specimen is slightly shorter with almost the same ? Communicated by permission of the Acting Director of the cal Survey of Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Ottawa Field-Naturalists' Club. Ottawa
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