We now come to the Rodentia, a very extensive and difficult order, in which there is still much difference of opinion as to the details of classification, although the main outlines are pretty well settled. The foundations of a true classification of this order were laid by Mr. G. R. Waterhouse more than thirty years ago, and succeeding authors have done little more than follow his arrangement with unimportant modifications. Professor Lilljeborg, of Upsala, has however made a special study of this group of animals, and has given an original and detailed classification of all the genera. (Systematisk Öfversigt af de Gnagande Däggdjuren, Glires. Upsala, 1866.) I follow this arrangement with a few slight modifications suggested by other naturalists, and which make it better adapted for the purposes of this work.
Order—RODENTIA.
| Fam. | |||||
| Murina (Waterhouse) |  | 55. Muridæ | Rats. | ||
| Simplicidentati |  | 56. Spalacidæ | Mole-rats. | ||
| 57. Dipodidæ | Jerboas. | ||||
| 58. Myoxidæ | Dormice. | ||||
| 59. Saccomyidæ | Pouched Rats. | ||||
| 60. Castoridæ | Beavers. | ||||
| 61. Sciuridæ | Squirrels. | ||||
| 62. Haploodontidæ | Sewellels. | ||||
| Hystricina (Waterhouse) |  | 63. Chinchillidæ | Chinchillas. | ||
| 64. Octodontidæ | Octodons. | ||||
| 65. Echimyidæ | Spiny Rats. | ||||
| 66. Cercolabidæ | Tree Porcupines | ||||
| 67. Hystricidæ | Porcupines. | ||||
| 68. Caviidæ | Cavies. | ||||
| Duplicidentati |  | Leporina (Waterhouse) | | 69. Lagomyidæ | Pikas. |
| 70. Leporidæ | Hares. | ||||
The Edentata have been classified by Mr. Turner, in the Proceedings of the Zoological Society (1851, p. 205), by Dr. Gray in the British Museum Catalogue, and by Professor Carus in his Handbuch. The former takes a middle course between the numerous families of Dr. Gray, seven in number, and the two families to which Professor Carus restricts the existing species. I therefore follow Mr. Turner.
Order—EDENTATA.
| Fam. | |||
| Bradypoda | 71. Bradypodidæ | Sloths. | |
| Entomophaga |  | 72. Manididæ | Scaly Ant-eaters. |
| 73. Dasypodidæ | Armadillos. | ||
| 74. Orycteropodidæ | Ant-bears. | ||
| 75. Myrmecophagidæ | Ant-eaters. | ||
The Marsupials have been well classified and described by Mr. Waterhouse in the first volume of his Natural History of Mammalia, and his arrangement is here followed. The suborders adopted by Professor Carus are also given.
Order—MARSUPIALIA.
| Fam. | |||
| Rapacia (Wagner) | | 76. Didelphidæ | Opossums. |
| 77. Dasyuridæ | Native Cats. | ||
| 78. Myrmecobiidæ | Native Ant-eater. | ||
| 79. Peramelidæ | Bandicoots. | ||
| Poephaga (Owen) | 80. Macropodidæ | Kangaroos. | |
| Carpophaga (Owen) | 81. Phalangistidæ | Phalangers. | |
| Rhizophaga (Owen) | 82. Phascolomyidæ | Wombats. | |
Order—MONOTREMATA.