The group is represented in India by the Spiny Dormouse Plata canthomys lasiurus, with a spiny coat ; and in China by the genus Typh/omys, with one species 7'. cinereus, a slate-grey coloured animal with a plumed tail.
The next family is the Muridae, the largest mam malian family; its typical members are mice of the House Mouse variety. The most important of the groups are the following :— Hydromyinae which contains the Australian Water Rats and various genera from the Philippines and New Guinea. Hydromys, the Australian and New Guinea Water Rats, has soft, thick fur and large laterally compressed tail. Chrotomys is an allied genus from Luzon, Philippines, which has the back prominently striped; size of body about that of a common rat (head and body 196 mm.; tail 110 mm.). Crunomys, probably an aquatic form related to the foregoing genus, and Celaenomys, which looks like Chrotomys without the stripes, are too closely allied genera also from Luzon.
a subfamily created to receive an extraor dinary Philippine rat with very reduced teeth; general form rather shrew-like, muzzle elongate.
A large subfamily is the Gerbillinae, with a number of genera, spread over a considerable portion of Africa and Asia. Of the African genera Gerbillus, Dipodillus and
extend into Asia. The majority of these animals have long, hairy tails and long feet ; others such as Microdillus, Desmo dillus, Desmodilliscus, and Pachyuromys, have short and fleshy tails. In most species the colour is bright buffy-brown or or ange above, white below. Taterona is found over the whole of Africa south of the Sahara; the closely allied Asiatic genus, Tatera, inhabits Peninsular India and Ceylon. Taterillus extends across Equatorial Africa from Nigeria to Kenya Colcny and the Sudan. The genus Gerbillus is found in south and northern Africa and India, and Dipodillus extends from West Africa to Kenya Colony and North Africa and India. Ammodillus and Microdillus are two dwarf forms from Somaliland. Desmodilliscus is a pigmy group from the Sudan and Northern Nigeria, and Desmodillus is the fat-tailed gerbil of South Africa; and Pachyuromys is a similar animal from North Africa. Psammomys is found in Northern Africa and Palestine, and Rhombomys, which resembles the fore going genus, comes from Russia, Siberia and Central Asia.
a subfamily which contains the Swamp Rats of Africa. The members of this group are all heavily built animals with long, soft fur and tails of medium length. The African Tree Mice and Rats and Fat Mice form another natural group, the Dendromyinae, which contains the Pigmy Tree Mice (Dendro mus) and the West African Bush Mouse (Prionomys batesi) ; both genera are remarkable for their semi-prehensile tails and long hind feet ; some of the Tree Mice have dark stripes on the back, where as Prionomys is pale chocolate in colour. The Spiny Tree Rats (Deomys) from West and Central Africa are remarkable for their long tails and spiny coats. The short-tailed members of this sub family are the Fat Mice (Steatomys) from South and West Africa, and the Mouse Gerbilles of Cape Colony.
By far the largest subfamily is the typical one, the Murinae, which contains a great number of genera, only a few of which it will be possible to deal with in this review.
The typical genus Mus is represented by the House Mouse and a few other species such as M. bactrianus from Northern India and M. muralis from St. Kildar ; about nine species of this genus are found in Europe ; it was originally confined to the Old World but has been introduced into nearly every part of the world. Closely allied is the genus Rattus, con taining the well-known Black and Brown Rats and over a hundred other forms. Much larger species are found in the allied genera Bandicota, Gunomys and Nesokia, the Bandicoot Rats which are found in India, Arabia and Northern Africa. In Africa there is a genus of Giant Rats known as Cricetomys, which measure about 2 ft. 6 in. in total length; the tail is very long and has a white tip. One of the most remarkable genera is Acomys, which contains the Spiny Mice, distributed over the greater part of Africa, south western Asia, Cyprus and Crete ; these Mice are almost as spiny as hedgehogs and vary in colour from uniform slaty-grey to bright red with white underparts. The Field Rats of Africa are included in three genera, Arvicanthis, uniformly coloured rats; Lemnis comys, rats with one or many stripes; and Rhabdomys, the four striped rats. Among the Australasian members of the subfamily mention may be made of the following :—Mastacomys fuscus, re sembles a common rat but with larger ears and broader molars. Capromys, a genus of naked-tailed, woolly rats with short, rounded ears ; two species are known, both from the Solomon Islands. Anisomys imitator, a coarse-haired rat with 6 mammae and only the basal part of the tail dark, the remainder yellowish-white (head and body 30o mm. ; tail 32o mm.). Mallomys, very large rats (head and body 470 mm. ; tail 400 mm.) ; fur very long with a number of white tipped hairs interspersed; the species are found in New Guinea. Hyomys meeki similar to Mallomys but rather smaller in size (head and body 390 mm.). The Australian Mice are numerous, the chief genus being Pseudomys. The Jerboa-Rats are included in the genus Conilurus, distinguished by their elongated hind-limbs and tufted tails; these rats are con fined to North Australia. A nearly allied genus is Mesembriomys from the Northern Territory; large rats with long jerboa-like tails. The subfamily Murinae, which contains more than fifty genera, is characterised by the molars being tuberculate, brachyodont, and rooted ; the tubercles of the cheek-teeth being arranged in three longitudinal rows. In addition to the genera already mentioned as occurring in Europe, the forms Epimys, Apodemus, and Micromys are also found in Europe ; the latter genus contains the well-known Harvest Mice, small reddish-orange coloured mice with semi-prehensile tails. The forms of Apodemus, the Field Mice, are widely distributed from Ireland to Japan. One of the most curious subfamilies of the Muridae is the Lophiomy inae, sometimes reckoned to be of family rank. It contains but a single genus, Lophiomys, the members of which are confined to East Africa; they differ from the typical Muridae in having the temporal fossa roofed over with bone ; the hair on the back forms a well marked crest. These animals are of considerable size, the head and body measuring 270 mm. in length.