Part 7 (1/2)

The similarities or differences in the baculum in Old World and New World representatives placed in the same genus or subgenus, or thought to be ”companion species” have been commented upon in accounts of _Lemmus_, _Dicrostonyx_, _Clethrionomys_, _Lagurus_, _Arvicola_, _Stenocranius_, _Chilotus_, _Chionomys_, _Pitymys_, and in accounts of _Microtus agrestis_ as compared with _M. pennsylvanicus_, and _Microtus oeconomus_ (both Old World and New World).

The baculum in the Microtinae more closely resembles the baculum in the Cricetinae of the Old World than in the Murinae, or than in any other rodents known to me. This resemblance suggests relations.h.i.+p between Microtinae and Cricetinae.

LITERATURE CITED

ARGYROPULO, A. I.

1933a. Die Gattungen und Arten der Hamster (_Cricetinae_ Murray, 1866) der Palaarktik. Zeitschr. f. Saugetierkunde, 8:129-149, 27 figs. in text.

1933b. uber zwei neue palaarktische Wuhlmause. Zeitschr. f.

Saugetierkunde, 8:180-183, 3 figs. in text.

CALLERY, R.

1951. Development of the os genitale in the golden hamster, _Mesocricetus (Cricetus) auratus_. Jour. Mamm., 32:204-207, 1 fig. in text.

CHAMBERLAIN, J. L.

1954. The Block Island meadow mouse, _Microtus provectus_. Jour. Mamm., 35:587-589, 2 tables in text.

DEARDEN, L. C.

1958. The baculum in _Lagurus_ and related microtines. Jour. Mamm., 39:541-553, 1 fig. in text.

DIDIER, R.

1943. L'os penien des Campagnols de France du Genre _Arvicola_.

Mammalia, 7:74-79, 10 figs. in text.

1954. Etude systematique de l'os penien des Mammiferes (suite), Rongeurs: Murides. Mammalia, 18:237-256, 14 figs. in text.

ELLERMAN, J. R.

1941. The families and genera of living rodents. Vol. II. Family Muridae. The British Museum (Natural History), London, pp. xii + 690, 50 figs.

FRILEY, CHARLES E.

1947. Preparation and preservation of the baculum of mammals. Jour.

Mamm., 28:395-397, 1 fig. in text.

HALL, E. R., and E. L. c.o.c.kRUM.

1953. A synopsis of the North American microtine rodents. Univ. Kansas Publ., Mus. Nat. Hist., 5:373-498, 149 figs. in text.

HAMILTON, W. J., JR.

1946. A study of the baculum in some North American Microtinae. Jour.

Mamm., 27:378-387, 3 figs. in text.