NOTICES OF NEW BOOKS. 187 
be allowed to live with them on the friendly terms mentioned by the 
observer. 
Mr. A. H, Swinton communicated a paper “On Display and Dances 
by Insects.” 
Mr. J. W. Slater communicated a paper ‘On the Secondary Sexual 
Characters of Insects.” 
Part V. of the ‘ Transactions’ for 1877, containing index, title-page, &c., 
was on the table—R. Mexpoua, Hon. See. 
NOTICES OF NEW BOOKS. 
The Rodents of North America. By Extiorr Cours and J. A. 
ALLEN; forming Vol. XI. of the Report of the United States 
Geological Survey of the Territories. F, V. Hayben, U.S. 
Geologist-in-charge. 4to, pp. 1100. Washington, 1877, 
THE liberal aid which is given to Science by the Government 
of the United States affords an example which the Government of 
this country would do well to imitate. By defraying the cost 
of printing important scientific works, the limited sale for which 
might deter most publishers from undertaking their publication, 
the State confers an inestimable boon, not only on students, but 
on the whole scientific world at large. 
The volume before us, which has been brought out under the 
auspices of the American Government, is one of the most important 
of the series that has yet appeared. It may be described as a very 
careful Monograph of the Rodents of North America, and from the 
well-known zoological ability of the authors it will assuredly form 
a text-book for all students of American Zoology. 
A contemporary thus ably epitomises the contents:—“ The 
classification adopted by the authors divides the order Rodentia 
into two well-known sub-orders, Stmplicidentati, with two, and 
Duplicidentati, with four, incisor teeth in the upper jaw, the latter 
including the Leporide, or true Hares, and the Lagomyide, ‘ Pikas,’ 
or Calling Hares, both of which families are treated by Dr. Allen. 
Of the nine families into which the much larger group of the 
Simplicidentati is divided, the Muride, Zapodide, Saccomyide, 
Haplodontide, and Geomyide are described by Dr. Coues; and 
the Sciuride, Castoride, Hystricide, and Casloroidide by Dr. 
