... of Shrews (Sorex) and in some field-mice (Arvicola), the Rev. L. Jenyns (Ann. Nat. Hist., vol. vii. pp. 267, 272) found the proportional length of the intestinal canal to vary considerably. He found the same variability in the number of the caudal vertebrae. In three specimens ... — Darwinism (1889) • Alfred Russel Wallace
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