Page:Encyclopædia Britannica, Ninth Edition, v. 16.djvu/637

Rh MOLE 609 and cylindrical, and, owing to the very anterior position of the forelimbs, the head appears to rest between the shoulders ; the muzzle is long and obtusely pointed, ter minated by the nostrils, which are close together in front ; the minute eye is almost hidden by the fur ; the ear is without a conch, opening on a level with the surrounding integument ; the forelimbs are rather short and very mus cular, terminating in broad, naked, shovel-shaped feet, the palms normally directed outwards, each with five subequal digits armed with strong flattened claws ; the hind-feet, on the contrary, are long and narrow, and the toes are provided with slender claws. The body is densely covered with soft, erect, velvety fur, the hairs uniform in length and thickness, except on the muzzle and short tail, the former having some straight vibrissae on its sides, whilst the latter is clothed with longer and coarser hairs. The fur is generally black, with a more or less greyish tinge, or brownish -black, but various paler shades up to pure white have been observed. The food of the mole consists chiefly of the common earth-worm, in pursuit of which it forms its well-known underground excavations. Its habits, so difficult to observe, were many years ago most patiently studied and described by M. Henri le Court. Like many other mammals the mole has a lair or fortress to which it may retire for security. This is constructed with much ingenuity. It consists of a central nest formed under a hillock which is placed in some protected situation, as under a bank, or between the roots of trees. The nest, which is lined with dried grass or leaves, communicates with the main-run by four passages, one of which only joins it directly, leading downwards for a short distance and then ascending again ; the other three are directed upwards and communicate at regular intervals with a circular gallery constructed in the upper part of the hillock, Avhich in turn communicates by five passages leading downwards and outwards with another much larger gallery placed lower down on a level with the central nest, from which passages proceed outwards in different directions, one only communicating directly with the main-run, while the others, curving round, soon join, or end in culs-de-sac. The main-run is somewhat wider than the animal s body, its walls are smooth, and formed of closely compressed earth, its depth varying according to the nature of the soil, but ordinarily from four to six inches. Along this tunnel the animal passes backwards and forwards several times daily, and here traps are laid by mole-catchers for its capture. From the main-run numerous passages are formed on each side, along which the animal hunts its prey, throwing out the soil in the form of mole hills. The mole is the most voracious of mammals, and, if deprived of food, is said to succumb in from ten to twelve hours. Almost any kind of flesh is eagerly devoured by captive moles, which have been seen by various observers, as if maddened by hunger, to attack animals nearly as large as themselves, such as birds, lizards, frogs, and even snakes ; toads, however, they will not touch, and no form of vegetable food attracts their notice. If two moles be confined together without food, the weaker is invariably devoured by the stronger. They take readily to the water in this respect, as well as in external form, resembling their (A.) i. 3, c., prm. |, m. x 2 (T. wogura). (B.) i. 3, c. ^, prm. |, m. | x 2 (T. europasa, casca, longirostris, micrura). (C. ) i. f, c. T, prm. f, m. x 2(7 . leucrura, leptura). (D.) i. f, c. %, prm. ^, m. $ x 2(7 . mosckata). Except in T. europ&a, the eyes are covered by a membrane. In T. micrura the short tail is concealed by the fur. T. europasa ex tends from England to Japan. T. casca is found south of the Alps, the remaining species are all Asiatic, and of them two only T. micrura and T. leucrura occur south of the Himalayas. (See Dobson, Mono graph of tJie Insect ivora, Part ii., 1883.) representatives on the North American continent. Bruce, writing in 1793, remarks that he saw a mole paddling towards a small island in the Loch of Clunie, 180 yards from land, on which he noticed molehills. The sexes come together about the second week in March, and the young generally from four to six in number which are brought forth in about six weeks, quickly attain their full size. The mole exhibits in its whole organization the most perfect adaptation to its peculiar mode of life. In the structure of the skeleton very striking departures from the typical mammalian forms are noticeable. The first sternal bone is so much produced anteriorly as to extend forward as far as a vertical line let down from the second cervi cal vertebra, carrying with it the very short almost quadrate cla vicles, which are arti culated with its an terior extremity and distally with the bu rn eri, being also con nected ligamentously with the scapula?. The forelimbs are thus brought opposite the sides of the neck, and from this position a threefold advantage is derived : in the first place, as this is the narrowest part of the body, they add but little to the general width, which, if in- creased, would lessen the power of move ment in a confined space ; secondly, this position allows of a longer forelimb than would otherwise be possible, and so in creases its lever power; and, thirdly, although the entire limb is rela tively very short, its anterior position en- Skeleton of Mole x ^ (lower jaw removed to ables the animal, when show base of skull). burrowin&quot; 1 to thrust c &amp;lt; calcanemn ; c.h., clavicular articulation of the thp r-lavvS&quot; T, far for humerus ; d., clavicle; e.c, external condyle of hu- tne ClaS SO lai I r- merus. ^ f emur; fh t fibula; /c, falciform bone ward as to be in a line (radial sesamoid); h, humerus; i.c, internal condyle with the end of the of humerus ; il, left iliac bone ; i.p, ranius of the iir-p ilium and pubis ; is., ischium ; l.d, ridge of insertion nee of latissinius dorsi muscle. lesser trochantcr; ot wnicu is evident, nt, mannbrium sterni; o, fourth hypapophysial se- Posteriorly,wefind the samoid ossicle ; ol, olecranon ; p., pubic bone widely hind limbs similarly separated from that of the opposite side ;pa. f patella; &amp;lt; +i p.m., ridge for insertion of pectoralis major muscle ; removed out Ol tlie pt ^ pectinca i eminence; r, radius; rl&amp;gt;, lirst rib; s, way by approximation plantar sesamoid ossicle corresponding to the radial of &quot;the llip-ioints to sesamoid (os falciform) in the maims; sc., scapula; the centre line of the J^*&quot; 11 &quot; articulation of the humerus; t, tibia; body. This is effected by inward curvature of the innominate bones at the acetabula to such an extent that they almost meet in the centre, while the pubic bones are widely separated behind. 2 The shortness of the ~ r lt is most interesting to observe how, in the golden moles (Chrysochloridae) of South Africa, the necessary modifications of the corresponding parts of the body and limbs fitting them for fossorial action and underground progression have been brought about in a totally different manner. In them the manubrium sterni is not anteriorly elongated, neither are the clavicles shortened ; but this is made up for by a deep hollowing out of the antero-lateial walls of the thorax, the ribs in these parts and the sternum being convex inwards, the long clavicles have their distal extremities pushed forward, and the concavities on the sides and inferior surface of the thorax lodge the thick muscular arms. 2 In Jacobs s Talpte Europe^ Anatome (Jena, 1816) this part of the pelvic wall (marked pt in the fig.) was identified with the symphysis XVI. 77