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Show 48 MR. M. F. WOODWARD ON THE [Jan. 5, There can be very little doubt that the Duplicidentata, as concerns their teeth, are the most primitive living Rodents ; and as the deciduous front incisors have almost disappeared in them, we could hardly expect to find them present in the more modified forms, where the teeth are reduced in number. It is, however, highly probable that we might find them in the Hare and possibly in Lagomys. Krause (17), in describing the deciduous teeth of the Rabbit, gives the formula i. -. pm. -•> which, as I have shown, is the correct one ; but although he gives the correct formula, he cannot have seen the small deciduous first incisors ; in fact, he says (op. cit. p. 1 99) " the four large incisors persist from the beginning " ; so that he counts the large cutting-incisors twice over, first in the deciduous and afterwards in the permanent dentition, solely on the grounds that they happen to be formed very early, when none but milk-teeth are present in the jaw. The discovery of these teeth is entirely due to Huxley, but as he only mentioned it in a passing footnote appended to a paper dealing with much wider questions, and as he never figured them, I append figures, in illustration of m y more detailed account of them. In concluding, I should like to express m y thanks to Mr. Oldfield Thomas for his kind assistance in allowing m e access to a fine series of Hyrax skulls in the British Museum, and to Prof. Howes for his valuable advice and suggestions during the progress of this work. V. List of References. 1. BLAINVILLE. Osteographie, t. vi. p. 38. 2. B R A N D T , J. F. " Ueber d. Gattung d. Klippschliefer (Hyrax)." Mem. Ac. Petersb. (7) xiv. 1869. 3. C U V I E R , F. Dents d. Mammif. 1825. 4. C U V I E R , G. Ann. d. Mus. Paris, t. iii. 1804, p. 177. 5. . Recherches s.l. oss. Fossil. 4th ed., t. iii. 1834, p. 253. 6. F L O W E R , W . H. " O n the Homologies of the Teeth of the Mammalia." J. Anat. Phys. vol. iii. 1869, p. 262. 7. . " O n the Milk Dentition of Mammalia." Trans. Odont. Soc. 1871. 8. . " On the Succession of the Teeth in the Marsupialia " Phil. Trans, vol. 157, 1867, p. 631. 9. FLOWER, W. II., & LYDEKKER. " Mammalia." Lond., 1891. 10. GEORGE. " Monogr. Anat. d. Daman." Ann. Sci. Nat. (6) t. i. 1874, Art. 9, pp. 83-86. 11. G E R V A I S . Hist. Nat. d. Mammif. 1855. 12. G I E B E L . Odontographie, p. 75, 1855. 13. . Bronn's Thier-Reich, Bd. vi. Abth. v. p. 118, 1875. 14. G R A Y , J. E. Cat. of Carniv. and Pachyderm. Mammalia Brit. Mus. 1869. |
