DESCRIPTION.—after Dr. Anderson, who first discovered and named this species: "Dark brown on the head, neck, shoulders, and sides passing into a deep black on the extremities, a very narrow white line passing backwards from behind the angle of the mouth to the shoulder; under surface brownish; the spiny hairs of the anterior part of the trunk flattened, grooved or ungrooved. The crest begins behind the occiput and terminates before the shoulders; the hairs are long, slender and backwardly curved, the generality of them being about 4½ inches long, while the longer hairs measure about six inches.
"They are all paler than the surrounding hairs, and the individual hairs are either broadly tipped with yellowish-white, or they have a broad sub-apical band of that colour. The short, broad, spiny hairs, lying a short way in front of the quills, are yellow at their bases, the remaining portion being deep brown, whereas those more quill-like spiny hairs, immediately before the quills, have both ends yellow tipped.
"The quills are wholly yellow, with the exception of a dark brown, almost black band of variable breadth and position. It is very broad in the shorter quills, and is nearer the free end of the quill than its base, whereas in the long slender quills it is reduced to a narrow mesial band. The stout strong quills rarely exceed six inches in length, whilst the slender quills are one foot long. Posteriorly above the tail and at its sides many of the short quills are pure white. The modified quills on the tail, with dilated barb-like free ends are not numerous, and are also white. There are three kinds of rattle quills, the most numerous measure 0·65 inch in the length of the dilated hollow part, having a maximum breadth of 0·21 inch, whilst there are a few short cups 0·38 inch in length, with a breadth of 0·17 inch, and besides these a very few more elongated and narrow cylinders occur."—'Anat. and Zool. Res.,' p. 332.
[SUB-ORDER DUPLICIDENTATA—DOUBLE-TOOTHED RODENTS.]
These rodents are distinguished by the presence of two small additional incisors behind the upper large ones. At birth there are four such rudimentary incisors, but the outer two are shed, and disappear at a very early age; the remaining two are immediately behind the large middle pair, and their use is doubtful; but, as Dallas remarks, "their presence is however of interest, as indicating the direction in which an alliance with other forms of mammalia more abundantly supplied with teeth is to be sought."
| Dentition of Hare. |
Another distinctive characteristic of this sub-order is the formation of the bony palate, which is narrowed to a mere bridge between the alveolar borders, or portions of the upper jaw in which the grinding teeth are inserted.
The following synopsis of the sub-order is given by Mr. Alston:—
"Incisors 4/2; at birth 6/2; the outer upper incisor soon lost; the next pair very small, placed directly behind the large middle pair; their enamel continuous round the tooth, but much thinner behind; skull with the optic foramina confluent, with no true alisphenoid canal; incisive foramina usually confluent; bony palate reduced to a bridge between the alveolar borders; fibula anchylosed to tibia below, and articulating with the calcaneum; testes permanently external; no vescicular glands. Two families."—'P. Z. S.' 1876, p. 97.