470 RODENTIA 
begins. The whole body moves forward slowly, always advancing 
in the same general direction in which they originally started, but 
following more or less the course of the great valleys. They only 
travel by night; and, staying in congenial places for considerable 
periods, with unaccustomed abundance of provender, notwith- 
standing all the destructive influences to which they are exposed, 
they multiply excessively during their journey, having families still 
more numerous and more frequently than in their usual homes. 
The progress may last from one to three years, according to the 
route taken, and the distance to be traversed until the sea-coast 
is reached, which in a country so surrounded by water as the 
Scandinavian peninsula must be the ultimate goal of such a journey. 
This may be either the Atlantic or the Gulf of Bothnia, according 
as the migration has commenced from the west or the east side of 
the central elevated plateau. Those that finally perish in the sea, 
committing what appears to be a voluntary suicide, are only acting 
under the same blind impulse which has led them previously to 
cross smaller pieces of water with safety. 
Cuniculus.'—Cranial and incisive characters those of Myodes, 
in the main, but the molars more of an Arvicoline type, the first 
upper one differing from that of all other members of the family in 
having seven prisms. Externally of the general shape of Myodes, 
but distinguished by the absence of external ears, the shortness and 
dense furring of the feet, the obsolete pollex with rudimentary 
nail, and the great length of the two middle claws of the manus. 
Represented by one species, the Banded Lemming (C. torquatus), of 
the Arctic region. 
Remains of both C. torquatus and Myodes lemmus occur in British 
Pleistocene deposits. 
Fiber.?—Closely allied to Arvicola, both externally and in cranial 
and dental characters, but with the tail nearly as long as the body 
(apart from the head), compressed, nearly naked, and reticulate. 
Feet incompletely webbed, and the whole body adapted for a 
thoroughly aquatic life. 
The Musk-Rat or Musquash (F. zibethicus, Fig. 209) is the only 
representative of this genus, and the largest member of the sub- 
family, the head and body being about 12 inches in length. It is 
rather a heavily built animal, with a broad head, no distinct neck, 
and short limbs; the eyes are small, and the ears project very little 
beyond the fur. The fore limbs have four toes and a rudimentary 
thumb, all with claws; the hind limbs are larger, with five distinct 
toes, united by short webs at their bases. The tail is laterally 
compressed, nearly naked, and scaly. The hair much resembles 
that of a beaver, but is shorter; it consists of a thick soft under- 
? Wagler, Isis, 1832, p. 1220. 
° Cuvier, Légons d’ Anatomie Compar. tab. 1 (1800). 
