single molar on each side and some imperfect incisors.),--sometimes having none except one molar on each side; but this, though characteristic of the breed, must be considered as a monstrosity. M. Girard (1/61. Quoted in 'The Veterinary' London volume 8 page 415.), who seems to have attended closely to the subject, says that the period of the appearance of the permanent teeth differs in different dogs, being earlier in large dogs; thus the mastiff assumes its adult teeth in four or five months, whilst in the spaniel the period is sometimes more than seven or eight months. On the other hand small dogs are mature, and the females have arrived at the best age for breeding, when one year old, whereas large dogs "are still in their puppyhood at this time, and take fully twice as long to develop their proportions." (1/62. This is quoted from Stonehenge, a great authority, 'The Dog' 1867 page 187.) With respect to minor differences little need be said. Isidore Geoffroy has shown (1/63. 'Hist. Nat. General' tome 3 page 448.) that in size some dogs are six times as long (the tail being excluded) as others; and that the height relatively to the length of the body varies from between one to two, and one to nearly four. In the Scotch deer-hound there is a striking and remarkable difference in the size of the male and female. (1/64. W. Scrope 'Art of Deer-Stalking' page 354.) Every one knows how the ears vary in size in different breeds, and with their great development their muscles become atrophied. Certain breeds of dogs are described as having a deep furrow between the nostrils and lips. The caudal vertebrae, according to F. Cuvier, on whose authority the two last statements rest, vary in number; and the tail in English cattle and some shepherd dogs is almost absent. The mammae vary from seven to ten in number; Daubenton, having examined twenty- one dogs, found eight with five mammae on each side; eight with four on each side; and the others with an unequal number on the two sides. (1/65. Quoted by Col. Ham. Smith in 'Nat. Lib.' volume 10 page 79.) Dogs have properly five toes in front and four behind, but a fifth toe is often added; and F. Cuvier states that, when a fifth toe is present, a fourth cuneiform bone is developed; and, in this case, sometimes the great cuneiform bone is raised, and gives on its inner side a large articular surface to the astragalus; so that even the relative connection of the bones, the most constant of all characters, varies. These modifications, however, in the feet of dogs are not important, because they ought to be ranked, as De Blainville has shown (1/66. De Blainville 'Osteographie, Canidae' page 134. F. Cuvier 'Annales du Museum' tome 18 page 342. In regard to mastiffs, see Col. H. Smith 'Nat. Lib.' volume 10 page 218. For the Thibet mastiff, see Mr. Hodgson in 'Journal of As. Soc. of Bengal' volume 1 1832 page 342.) as monstrosities. Nevertheless they are