[42] J. Hunter shows that the long period of seventy-three days given by Buffon is easily explained by the bitch having received the dog many times during a period of sixteen days (‘Phil. Transact.,’ 1787, p. 353). Hunter found that the gestation of a mongrel from wolf and dog (‘Phil. Transact.,’ 1789, p. 160) apparently was sixty-three days, for she received the dog more than once. The period of a mongrel dog and jackal was fifty-nine days. Fred. Cuvier found the period of gestation of the wolf to be (‘Dict. Class. d’Hist. Nat.’ tom. iv. p. 8) two months and a few days, which agrees with the dog. Isid G. St.-Hilaire, who has discussed the whole subject, and from whom I quote Bellingeri, states (‘Hist. Nat. Gén.,’ tom. iii. p. 112) that in the Jardin des Plantes the period of the jackal has been found to be from sixty to sixty-three days, exactly as with the dog. [43] _See_ Isid. Geoffroy St.-Hilaire ‘Hist. Nat. Gén.,’ tom. iii. p. 112, on the odour of jackals. Col. Ham. Smith in ‘Nat. Lib.,’ vol. x. p. 289. [44] Quoted by Quatrefages in ‘Bull. Soc. d’Acclimat.,’ May 11th, 1863. [45] ‘Journal de la Physiologie,’ tom. ii. p. 385. [46] _See_ Mr. R. Hill’s excellent account of this breed in Gosse’s ‘Jamaica,’ p. 338; Rengger ‘Säugethiere von Paraguay,’ s. 153. With respect to Spitz dogs, _see_ Bechstein’s ‘Naturgesch. Deutschlands,’ 1801, B. i. s. 638. With respect to Dr. Hodgkin’s statement made before Brit. Assoc. _see_ ‘The Zoologist,’ vol. iv. for 1845-46 p. 1097. [47] ‘Acta Acad. St. Petersburgh,’ 1780, part ii. pp. 84, 100. [48] M. Broca has shown (‘Journal de Physiologie,’ tom. ii. p. 353) that Buffon’s experiments have been often misrepresented. Broca has collected (pp. 390-395) many facts on the fertility of crossed dogs, wolves, and jackals. [49] ‘De la Longévité Humaine,’ par M. Flourens, 1855, p. 143. Mr. Blyth says (‘Indian Sporting Review,’ vol. 2 p. 137) that he has seen in India several hybrids from the pariah-dog and jackal; and between one of these hybrids and a terrier. The experiments of Hunter on the jackal are well-known. _See also_ Isid. Geoffroy St.-Hilaire, ‘Hist. Nat. Gén.,’ tom. iii. p. 217, who speaks of the hybrid offspring of the jackal as perfectly fertile for three generations. [50] On authority of F. Cuvier quoted in Bronn’s ‘Geschichte der Natur,’ B ii. s. 164. [51] W. C. L. Martin ‘History of the Dog,’ 1845, p. 203. Mr. Philip P. King, after ample opportunities of observation, informs me that the Dingo and European dogs often cross in Australia. [52] Rüppel ‘Neue Wirbelthiere von Abyssinien,’ 1835-40 ‘Mammif.,’ s. 39 pl. xiv. There is a specimen of this fine animal in the British Museum. [53] Even Pallas admits this; _see_ ‘Act. Acad. St. Petersburgh,’ 1780, p. 93. [54] Quoted by I. Geoffroy, ‘Hist. Nat. Gén.,’ tom. iii. p. 453.