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garh, presented by the late Mr. Andrew Anderson, which yield skulls the exact counterpart of the skull figured by Peters as Spalacomys indicus, and these rats agree with the figure of A. indica, and with the description of Nesokia hardwickii. Hodgson described, in 1846, a rat from Nepal which he called Mus hydrophilus* and which Gray first regarded as an Arvicola, and afterwards as a Nesokia. He described it as characterised by its small ears, hardly above one-third the length of the head, also by its short tail "and by its fine and short pelage: the head he described as larger and the muzzle thicker than in the common land rats; ' above dusky brown; below and the limbs nearly white. Long piles inconspicuous. Snout to vent 3 inches; tail 2; head 14; ears; palm; planta .' These characters would seem to indicate a rat allied to the so-called Nesokia or Spalacomys, Peters, but I hesitate to pronounce any decided opinion on the species. In connection with the name of hydrophilus given by Hodgson to this rat, I have observed that the common Nesokia of Lower Bengal, which I propose to name Mus (N.) blythianus after Blyth, who did so much to forward the progress of Natural History in India and to enlarge our knowledge of this group, manifests a remarkable capacity, for a rat of its type, to take to water, when hard-pressed. Its burrows are frequently constructed on the banks of tanks in Lower Bengal, and when the rats are being dug out, they will freely take to the water, if that is their only way of escape, and swim considerable distances. To test this aquatic power, I had two rats placed in a large wire bird-cage, and the cage partially submerged. If the rats, when in those circumstances, were much annoyed, they immediately dived to the bottom of the cage, where they could be observed running about under water. I also had them removed from the cage, and let loose in the large sheet of water in the Zoological Gardens, between the two iron bridges. When let loose at the bank, and an attempt was made to catch them, they immediately dived, and the stronger of the two did not. appear at the surface for some time, when it was observed at a considerable distance from the bank, making for the opposite side.

I have already referred to the name given by Elliot to the allied form from Madras, viz., M. providens. He records of it that it stores up large quantities of grain during harvest. The natives of Bengal ascribe a similar habit to M. (N.) blythianus, and it has been stated to me that sometimes considerable quantities of grain may be found in a burrow, and that the natives being aware of this habit make raids on these murine granaries.

With reference to the characters of the genus Nesokia, Gray, the examination of a large series of skulls of M. hardwickii and of the other species shows that the dental features selected by Gray are essentially

* Ann. and Mag. Nat. Hist. Vol. XV, 1845, p. 267; Cat. Sp. and Draw. Mamm. &c. Hodgson, Nepal, Coll. Brit. Museum, 1846, p. 19; l. c. 1863, new ed., p. 10.

those of worn teeth, and that they do not contain the characters of the dentition as seen in the teeth before they are worn. In the latter condition, each of the three lamina of the first upper molar presents a large central cusp, and a much smaller or even minute cusp on either of its sides, resulting as it were from the sinuous characters of each lamina of the tooth. In true mice and ordinary rats, the lamina are transversely more sinuous and smaller, whereas in Nesokia they are large and transverse without any marked sinuosity, in the more typical forms. In the second upper molar, there are only two lamina, the first being abortive and only represented by a small isolated cusp attached to the anterior face of the inner cusp or fold of the first of the two laminæ, which is exactly the same arrangement as in Mus. The last molar, except in having its laminæ more regularly transverse than in Mus, resembles the same tooth in this latter genus. In the lower jaw, there is the same regularly transverse character in the larger laminæ as compared with Mus, but all the cusps are the same. In the large rats of the type of M. giganteus, Hardwicke, the teeth conform more to the type characteristic of the ordinary rats and mice, the laminæ, however, being relatively larger than in Mus and less sinuous, but taking the dentition as a whole, in connection with the form of the skull, these large rats are more closely allied to Nesokia than to the true rats, an opinion which was first held by Sir Walter Elliot.*

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The incisor teeth of a Nesokia are always broader than those of an ordinary rat, and in this respect are more chisel-shaped, but the incisor teeth of the large rats such as M. giganteus are also proportionally broader than those of ordinary rats.

In the adult animal, such as that figured by Prof. Peters, the laminæ are very regularly transversely oblong without any trace of such cusps as those I have described; and in old individuals of the larger rats, such as M. giganteus, the teeth I have observed to be worn down, much in the same way as in the so-called Nesokia Spalacomys. Considering these facts, it does not appear that the genus Nesokia has any ground to recognition on characters derived from the dentition. The points in which the skulls of rats referable to the type of M. (Nesokia) hardwickii, Gray, (Spalacomys indica, Peters,) differ from those of the ordinary rats and mice are, on the other hand, much more pronounced than any difference in their dentition. The skull of Nesokia is a much broader and shorter skull with a short stout muzzle and expanded zygomata. The brain case is much shorter and broader than that of any member of the genus Mus. The temporo-parietal ridges also are proportionally nearer each other than in Mus, and the upper surface of the parietals is more flattened. The anterior palatine foramina are much

* Madr. Journ. Lit. and Sc., Vol. X, p. 209. Sir W. Elliot erroneously regarded M. providens and M. giganteus as belonging to the genus Neotoma.

more closed than in ordinary rats and mice, and in some of the more typical Nesokiæ, such as M. (N.) hardwickii, they are almost closed. There is also this further difference, that the palate of Mus-Nesokia contracts more anteriorly than in Mus, and is always proportionally narrower, with a much shorter edentulous interspace behind the last molar than in Mus. In the larger rats, such as M. giganteus, the posterior portion of the palate, in this respect, corresponds to Mus-Nesokia, and the features of the palate generally are more Mus-Nesokian, than those of true Mus. The palate also of Mus-Nesokia is marked by two somewhat pronounced longitudinal furrows which are the backward prolongations of the anterior palatine foramina. These grooves, near their hinder extremities, have the posterior palatine foramina lying in their course, and beyond them they are prolonged over the posterior margin of the palatines where they nearly constitute a closed canal by the inward projection of the inner palatine border of the maxilla and the somewhat thickened and anteriorly recurved posterior margin of the palatines. This arrangement is seen to occur only in a very feeble degree in ordinary rats and mice which, however, have not, as a rule, any thickening of the hinder margin of the palatines. Like the majority of thoroughly burrowing rodents, the tympanics are relatively much larger than in the ordinary rats. The large rats (M. giganteus) have the palatine features and the tympanics of Mus-Nesokia. These giant rats have rather more elongated skulls than the more typical Nesokians and, in this respect, they serve to connect the latter with the generality of mice and rats, but in their other features they more resemble Mus-Nesokia than Mus. I would therefore regard them as constituting a section of the sub-genus Nesokia. This view was first put forward by Sir Walter Elliot, so long ago as 1839, and Blyth agreed with him in regarding the affinities manifested by the great bandicoot rats as thoroughly Nesokian, and in the propriety of separating all of these Nesokian species from the typical forms of mice.

After a careful consideration of the characters which these various species display, it appears that this sub-genus of Mus may be conveniently divided into three sections; 1st, one section containing such forms as Mus (Nesokia) hardwickii, M. (N.) huttoni, M. (N.) scullyi, the more typical species of Nesokia, all characterised by broad incisors regularly laminated, large molars and small anterior palatine foramina, with tails considerably shorter than the body; and the females possessing only 4 pairs of mammary teats, two inguinal, one axillary and one pectoral: 2nd, another section comprising M. (N.) providens, M. (N.) blythianus (n. s.) and M. (N.) barclayanus (n. s.), distinguished by somewhat narrower incisors, smaller and less regularly tranversely laminated molars, more open anterior palatine foramina and longer tails; with the females possessing as many as even 7 to 9 pairs of

mammary teats*: and, lastly, a third division containing M. (N.) giganteus and M. (N.) elliotanus, (n.s.) the so-called bandicoot rats, with longer skulls, broad incisors, with molars of the type of the second section, but proportionally somewhat larger with less wavy lamina, longer anterior palatine foramina and tails nearly equalling the length of the body and head. I have largely collected rats for the Indian Museum from all parts of India, and out of the materials brought together I am enabled to determine the following species belonging to the sub-genus Nesokia.

1st Section.

MUS. (NESOKIA) HARDWICKII, Gray.

? Arvicola indica, Gray, Gray and Hardw., Ill. Ind. Zool., Vol. I, 1832, Pl. XI.

Mus. hardwickii, Gray, Mag. Nat. Hist. (Charlesworth), Vol. 1, 1837, p. 585.

Nesokia hardwickii, Gray, Ann. and Mag. Nat. Hist., Vol. X, 1842, p. 265, List Mamm. of 1843, p. 113; Jerdon, Mamm. Ind. 1867, p. 190. ? Mus hydrophilus, Hodgson, Ann, and Mag. Nat. Hist., Vol. XV, 1843,

p. 267.

p. 267.

? Mus pyctoris, Hodgson, Ann. and Mag. Nat. Hist., Vol. XV, 1845, Nesokia griffithii, Horsfd., Cat. Mamm. East Ind. As. Mus., 1851, p. 145.

Spalacomys indica, Peters, Abhand. der K. Akad. Wissensch. zu Berlin, 1860, p. 143, Taf. IV, fig. 1.

The head short and bluff, much shorter and broader than in M. (N.) providens and M. (N.) blythianus ; the muzzle broad and deep, and in these respects it resembles (N.) huttoni. The eye moderately large and situated about half way between the ear and the end of the muzzle. Ears not large, smaller than in these other two species, rounded, seminude, but clad with minute hairs. Tail variable, but much shorter than in M. (N.) providens, and M. (N) blythianus, seldom exceeding the distance between the vent and the middle of the neck, but shorter than in M. (N.) huttoni : ringed, nearly nude, less clad than in M. (N.) providens and M. (N.) blythianus, with minute hairs. Feet well developed, smaller than in M. (N.) huttoni; claws moderately long; the upper surface of the feet sparsely clad.

The fur is generally soft and moderately long, but not so silky as M. (N.) huttoni : it varies however in this respect and is sometimes somewhat

* Hodgson described a rat, as M. plurimammis from Nepal and the Terai, which, from the description and the proportional length of its tail appears to be an allied species.

harsh. The pelage, as in the other species, consists of three kinds of hairs, short under-lying fur, and ordinary hairs, intermixed among which, especially on the dorsal and sacral regions, are numerous long black hairs which project a long way beyond the fur, as in M. (N.) blythianus,* but not to the same extent. The general colour of the animal on the upper parts is sandy brown or fawn, paler on the sides, and dusky grey with a tinge of yellowish rufous on the under-surface. The muzzle, feet and tail are fleshcoloured, and the ears are of the same colour but somewhat darker.

Mr. Blanford† has pointed out that M. (N.) hardwickii is a much larger animal than M. (N.) huttoni. The measurements of the largest male, M. (N.) huttoni, mentioned by him are as follows, taken from the fresh animal, viz.

Length of body and head,...
Length of tail,

Length of hind foot,

7711

4" 6

1′′.6

whereas the largest male, out of an extensive series of this rat in alcohol, collected by the late Mr. Andrew Anderson at Fatehgarh, gives the following dimensions:

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Besides differing in size these species would appear also to differ in the relative proportions of the tail and the feet, the latter being somewhat larger in M. (N.) huttoni, than in M. (N.) hardwickii. The M. (N.) griffithi of Horsfield in its proportion agrees with this species. If two female examples of the two species from the same localities are compared, we have similar results, thus—

M. (N.) huttoni. M. (N.) hardwickii. 요

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6":45

4".15

1":25

I am indebted to Dr. Dobson for having compared the foregoing male specimen from Fatehgarh with the type in the British Museum, with which he pronounces it to agree.

The skulls, however, are remarkably alike and the only differences I can detect are, that the molar teeth of animals by their other characters referable to M. (N.) huttoni, are somewhat larger than those of M. (N.) hardwickii, the anterior palatine foramina of the latter being a little shorter

* These piles are not shown in the figure of the species in the Zoology of Persia. + Zool, of Persia, p. 59.

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