Allen. Of these groups the Zapodidæ constitute a family established for the reception of a single species—the Long-legged Mouse or Jumping Mouse, originally described as a Jerboa, under the name of Dipus hudsonius, but which, according to Dr. Coues, exhibits characters distinguishing it quite as much from the true Dipodidæ as from the Muridæ. The family Castoroididæ is a new one, proposed for the reception of the great extinct Rodent, Castoroides ohioensis, the remains of which have been obtained from post-tertiary deposits in various parts of North America. This animal, which was about the size of an adult black bear, was long supposed to have been a gigantic beaver. Dr. Allen, however, places it in the Hystricine group. It is the largest known Rodent, except an extinct Capybara (Hydrochœrus) described by Lund, from the Brazilian Bone Caves.
"Each of the above families is treated monographically, its position in the system being discussed, its genera and species, and the habits of the latter, described, and its bibliography given. Under some of the families, the extinct North American species belonging to them are noticed, and in an appendix Dr. Allen gives a list of the known extinct Rodentia of North America, with short notices of those not referred to in the monographs. A second Appendix contains a valuable bibliographical list of works relating to North American Mammals, by Dr. T. Gill and Dr. Coues; and the volume is illustrated chiefly with wood engravings of the skulls of Muridæ."
This is another of the American Government publications, of smaller size than the work last noticed, but of no less importance and value. It forms Volume VI11. of the 'Miscellaneous Publications' issued by the U.S. Geological Survey Department, under the able superintendence of Dr. Havden, and, relating as it does to a group of animals on which a large majority of mankind are more or less dependent for warm covering, it may be said to possess a greater interest for the general public than most scientific works of the kind usually do.
