1896.] GENERA OF RODENTS. 1021 
92. Evotomys, Coues. 
P, Ac. Philad. 1874, p. 186. 
93. Microtus, Schrank. 
Fauna Boica, i. p. 66 (1798). [Arvicola, 
Lac. Mém. de I’Inst. iii. p. 495 (1801).] 
(6) 94. Synaptomys, Bd. 
Mamm. N. A. pp. xliv, 558 (1857). 
95. Lemmus, Link. 
Zool. Beytr.i. pt..2, p. 75 (1795). [Myodes, 
Pall. Zoogr. Ross.-Asiat. p. 173 (1811).] 
96. Dicrostonyx, Glog. 
Naturgesch. p. 97 (1841). [Cuniculus, 
Wael. Isis, 1832, p. 1220.] 
(c) 97. Ellobius, Fisch. 
Zoognosia, iii. p. 72 (1814). 
L. SIPHNEINZ’. 
98. Siphneus*, Bts. 
Het geslacht d. Muizen, p. 20 (1827). 
VII. Spalacide °*. 
A. RHIZOMYINZ, 
99. Rhizomys, Gray. 
P. Z.8. 1831, p. 95. 
1 Mr. Gerrit Miller, to whose paper on Voles and Lemmings I am much 
indebted, has thrown doubt on the validity of the Siphneine as a subfamily 
(N. Am. Fauna, no. 12, p. 8, footnote, 1896), and in so far as regards EVobius, 
hitherto always put with Siphneus, he is apparently correct, as its differences 
from the Voles and Lemmings do not seem to be much greater than those that 
separate these two groups from each other, and the Voles, Lemmings, and 
Ellobius may suitably form three groups of the subfamily Microtine. J have 
had to reverse the order of the genera from that given by Mr. Miller, in 
order to bring the Murine Phenacomys and Evotomys towards the Muride, 
Synaptomys towards the Voles, and the Lemmings, as a whole, towards Ellobius, 
With regard to Siphneus itself, however, I think its peculiarities are amply 
sufficient to necessitate its being set over against all the rest of the group in a 
subfamily by itself. The modification that its anteorbital foramen has under- 
gone, in comparison with that of the Microtine, is, however, curiously paralleled 
by that of the widely different Spalacide, and may be simply an adaptive 
modification due to a strictly talpine life. But in any case its differences, both 
external, cranial, and dental, are clearly sufficient to demand separate subfamily 
rank. 
2 Dr. J. A. Allen, Bull. Am. Mus. N. H. vii. p. 183 (1895), considers Kerr’s 
Myotalpa should replace Siphneus ; but as the result is attained by a method 
about the detailed working of which opinions are still divided, I provisionally 
use the better-known term. 
3 Not only do the Bathyerging of Alston’s Spalacidz of course go off to form 
aseparate family, butit is very doubtful whether Spalax and Rhizomys, combined 
by him in the Spa/acine, are rightly put even in one family, their resemblances 
being perhaps more adaptive than genetic. Winge puts Rhizomys with the 
Muridx, and Spalar with the Dipodide, but does not give sufficient reasons 
for these allocations. This is one of those cases where a myological investigation 
is likely to be of much service ; and the group is commended to the attention of 
Mr. Parsons, whose recent papers on Rodent myology have been of much 
