FAMILY H EMICLAVICULATA. WITH IMPERFECT COLLAR BONES. 



39 



Three varieties of the Musquash have been observed ; one entirely black, 

 which is very rare, another pied with blackish-brown patches on a white 

 ground, and a third white or albino, which is not very rare. 



SACCOMYS Pouched Mouse. The species S. Anthophilus is a native of 

 North America ; it is clothed with a silky fur of a light tawny-brown colour, 

 and its habits are not very dissimilar to those of Squirrels. 



SACCOPHORUS Pouched Rat. The species are the Canadian, the Mex- 

 ican, the Columbian, the Umber, and the Mole-sltaped Pouch Rat all natives 

 of America. 



SCIURUS Squirrel. The Squirrels are remarkable for the elegance and 

 activity of their motions, as well as for personal beauty, which is materially 

 increased by their extreme cleanliness. They are especially formed for 

 climbing, and then: muscular strength is very great. The springs which 

 they take from branch to branch, or from tree to tree, whilst playing with 

 each other, or in avoiding pursuit, are very astonishing ; and if no tree be 

 sufficiently near for them to spring to, they drop, without injury, to the 

 ground from heights which might be expected to crush them. On the ground 

 they move by repeated short leaps, whilst their long tail waves gracefully 

 over them. When listening or feeding, they sit upright on their haunches, 

 with the tail raised against the back, and its point gradually dropping 

 towards the ground. They hold the nuts, upon which they mostly feed, 

 principally between the rudimental thumbs and adjoining palms, turning the 

 nut about till the thinnest part of the shell is found, into which a narrow 

 aperture is soon made with the teeth sufficient to admit the points of the 

 lower front teeth, by which successive pieces of the shell are broken off till the 

 kernel is exposed. As their food is not to be obtained throughout the year, 

 they lay up hoards of nuts and grain against the winter, and so well do they 

 remember where these deposits are made, that they have no difficulty in 

 finding them even when deeply covered by snow. To these they occasion- 

 ally resort, when the weather is fine, 

 to feed, and then returning to their 

 nest or drey, as it is called, and which 

 is usually but at a short distance, fall 

 asleep, and continue till awakened by 

 the calls of hunger : they cannot 

 therefore be said to hybernate com- 

 pletely. They build their nests in 

 holes of trees, or in the forks of their 

 branches, and the nest consists of 

 sticks and moss laid together and 

 lined with fur, wliich the female 

 pulls from her breast when about to 

 bring forth her young. They are 

 extremely prolific when undisturbed, 

 and commit great ravages in the fields: this was and still is the case in 

 America and India, where the country is not so thickly inhabited. Godman 

 mentions, that in the United States they in some seasons migrate in large 

 bodies from one district to another, and are not stopped in their course, 

 although great numbers are destroyed by beasts and birds of prey, and in 

 crossing the rivers. They are generally distributed throughout all parts of 

 the world, except in New Holland, and live in the woods. 



True Squirrels have the tail dichotomous ; profile nearly vertical ; brain- 

 case exceeds two-thirds of the length of the head ; in some the ears are 

 tufted, but in others plain. They are thus divided: 1. Those with the 

 ears tufted : the Common Squirrel (S. Vulgaris), the Alpine, the Malabar, 

 the Madagascar, the Great-tailed, the Hudson's Bay, and Elphinstone's 

 Squirrel. 2. Those with ears not tufted : the Cat Squirrel, the Fox, the 

 Grey, the Black, the Varied, the Plantain, the Javan, the Golden-bellied, the 

 Blackish, the Black-banded, the White-striped, the Anomalous, the Ocular, 

 the Congo, Leschenhault's, Clark's, and Prewst's Squirrel. 



The Guerlingets have the tail cylindrical or dichotomous only at its tip ; 

 middle of the forehead deeply flattened, its upper part elevated, as are also the 

 upper and hind parts of the head ; the breadth of the forehead equal to its 

 height, and the brain-case forming two-thirds of the length of the head ; 



Squirrel. 



ears not tufted. They include the Double-handed, the White-banded, the 

 Beautiful, and several other species of Squirrel. 



SPERMOPHILUS or Spermophile. These animals differ from the Marmots 

 in a few particulars, thereby forming a transition from the Marmots, Arctomys, 

 to the Ground Squirrels, Tamias, and are found in the northern parts of 

 Europe, Asia, and America, and the intervening islands. 



TAMIAS Ground Squirrel. These animals differ from the True Squirrels 

 (Sciurus) in a few anatomical characteristics, and still more so in their 

 habits. Their claws are less sharp than in the Squirrels, which, together 

 with the soles of the feet not being capable of inclination towards each other, 

 render them less suited to climb trees, although enabling them to move 

 along the ground and to dig their burrows with greater facility ; hence their 

 common name of Ground Squirrels. 



Among the species we find the following : the Striped, the Four-lined, 

 the Hudson's Bay, and the Line-tailed Ground Squirrel all natives of the 

 New World. 



Family WITH IMPERFECT COLLAR BONES ; Henudaviculata. 



The clavicle in the members of this family is so imperfectly developed 

 as to merit the designation given them ; that organ being so small as 

 scarcely to fulfil its proper functions. 



ILLUSTRATIVE EXAMPLES. 

 PLATE 13. 



Genera. Species. Common Name. 



Lepus ------ Timidus - - Common Hare. 



Lepus vel Lagomys - - Pusillus - - - - Calling Hare. 



Pteromys ----- Sabrinus - - - - Great Flying Squirrel. 



Hystri* ------ Cristata - - - - Common Porcupine. 



Other Genera of this Family: Bathyergus, Cana, Cheiromys, Chlo- 

 romys, Ccelogenus, Hydrochosrus, Loncheres. We may also add the genus 

 Spalax, family Murides. 



CHARACTERS OF THE GENERA. 



1. LEPUS. Incisive teeth, four in the upper jaw, placed in two rows, the 

 front two large, wedge-shaped, grooved longitudinally in front, the hind 

 two very small, cylindrical, and flattened from before to behind, and applied 

 closely to the back of the first row ; two in the lower jaw wedge-shaped 

 also ; no cuspid teeth ; molars six of a side in the upper jaw, the hind one 

 very small, five below, their crowns flat with transverse projecting edges of 

 enamel ; muzzle sharp ; ears long ; body covered with hair ; tail very short, 

 generally turned up ; teats pectoral and inguinal ; fore legs short, five-toed, 

 hind legs very long, four-toed ; soles of the feet hairy ; claws falcular. 



2. PTEROMYS (Gr. irTcpoy, a icing, and ftvt, a mouse'). Incisive teeth two 

 in each jaw, the upper wedge-shaped, and their anterior surface smooth, 

 lower compressed and pointed ; molar teeth five on a side in the upper and 

 four in the lower jaw, close set, simple, tritorial ; muzzle bluntish ; upper 

 lip cleft ; ears roundish ; fore feet four-toed, and with a thumb ; hind feet 

 five-toed ; skin of the sides of the body extended to the limbs, and forming 

 a kind of false wing ; tail long, roundish, and hairy. 



3. HYSTRIX (Gr. 0p<, a hair or bristk). Incisive teeth two in each jaw, 

 wedge-shaped, molar five on a side in each jaw, cylindrical ; body covered 

 with strong and sharp quills, projecting beyond others shorter, or from 

 among hair or wool ; tail variable in length ; feet four-toed in front, five- 

 toed behind, armed with strong claws. 



4. BATHYERGUS (Gr. paGvepyttv, to work deeply in the earth). Incisor 

 teeth large, not covered by the lips, and wedge-shaped ; canine none ; 

 grinders four on either side, above and below, the posterior sloping deeply 

 outwards ; muzzle broad ; eyes small ; auricles none ; tail short and bristly ; 

 toes five on each foot, short and armed with thin flat nails. 



5. CAVIA. Four toes before, and three behind, separate and armed with 

 broad nails ; the molar teeth having but a single lamina notched singly on 

 the inner edge in those of the lower jaw, and on the outer edge of those in 

 the upper ; no tail. 



