386 OENIIHOKHTifCHIB^. 



both indicate a relationship to premolars or molars rather than to 

 incisors or canines. Their number, so far as is at present known, is 

 probably four in each jaw above and below, making sixteen in all*. 



Functionally, however, teeth are represented in this family by 

 strong horny plates developed from the palate-ridges, and serving, 

 by their power of continuous growth, to make up for the rapid wear 

 caused by the gritty nature of the food. 



Range. Australian subregion. 



References to the Literature hearing on the Anatomy, Embryology, 

 Reproduction, Physiology, Sfc. of the Ornithorhynohidse. 



Banks, Voigt's Mag. iii. p. 724 (1801). 

 Home, Phil. Ti-ans. 1802, p. 67, pis. ii.-iv. 

 Mbckbl, Beytr. vergl. Anat. i. Heft i. p. 64, pi. ix. (1809). 

 Blainville, Bull. Soc. Philom. 1817, p. 82 (spur and gland). 

 E. Geopproy, Philos. Anat. pp. 114 & 126, pi. ii. fig. 19 (1818) (respi- 

 ratory organs). 

 Jamieson, Tr. Linn. Soc. xii. p. 684 (1818) (poisonous effects of blow 



from spur). 

 Home, Phil. Trans. 1819, p. 234, pis. xvi.-xix. (ovaries and ova). 

 RuDOLPHi, Abh. Ak. Berl. 1820-21, p. 232 (spur). 

 Hill, Tr. Linn. Soe. xiii. p. 622 (1822) (poison-gland, habits, &c.). 

 JaefA, De Ornithorhyncho paradoxo, Diss. Univ. Berol. pis. i. & ii. 



(1823) (osteology). 

 D'Alton, Osteol. Zahul. Thiere, pis. i. & ii. (1824) (osteology). 

 Knox, Mem. Wern. Soc. v. pp. 26 & 144, pis. i., v., & vi. (18U). 

 Blainville, N. Bull. Soe. Philom. 1826, p. 138. 

 E. Qeoppeoy, Ann. Sci. Nat. ix. p. 457 (1826). 

 Meckel Ornithorhynchi paradoxi, Descriptio anatomica, pis. i.-vii. 



(1826). 

 Id. Meckel's Arch. i. Nat. x. p. 23 (1827) (abdominal glands). 

 E. Gboppkoy, M6m. Mus. xv. pp. 1-48, pla. i. & ii. (1827) (sexual 



organs). 

 I. Gboppboy, Diet. Class. d'H. N. xii. p. 592 (1827). 

 E. Gboppboy, Ann. Sci. Nat. (1) xviii. p. 157, pi. iii. fig. 4 (egg) (1829). 

 Owen, Phil. Trans, cxxiii. p. 517, pis. xv.-xviii. (1832) (mammary 



glands). 

 Blainville, N. Ann. Mus. ii. p. 369, pi. xii. (1833) (reproduction). 

 E. Geoffbot, p. Z. S. 1833, pp. 28 & 91 (abdominal glands). 

 Owen, P. Z. S. 1834, p. 43 ; id. Tr. Z. S. i. p. 221, pis. xxxii. & 



xxxiii. (animal, young, and viscera) (1834). 

 Id. Phil. Trans, cxxv. p. 555, pi. xxv. (1834) (ova) 

 G. OuviBB, Oss. Foss., Atl. pi. ccxv. (skeleton) (1836). 

 Owen, Cyclop. Anat. iii., Art. " Monotremata," pp. 366-407, figs. 168- 



202 (1842). 

 VBBBEAtrx, Rev. Zool. 1848, p. 127 (habits and reproduction). 

 Maybb, Arch. f. Nat. xv. p. 81 (1849). 

 Hyetl, SB. Ak. Wien, viii. p. 33 (1852) (arterial system). 



* This account is taken from the foUowing paper, in which all that is as yet 

 known about the teeth of OrnithorhyTtchvs is contained ; — Poulton, E. B., "The 

 True Teeth and the Horny Plates of Ornithorhynchus," Q. J. Micr. Sci. xxix. 

 p. 9 (1888). 



