Reproduction in the common shrew ( Sorex araneus Linnaeus) I—The oestrous cycle of the female

This paper describes the reproductive processes of the Common Shrew so far as they can be determined from animals caught in the wild state. No account seems to have been given of the oestrous cycle of this species and existing knowledge regarding its life history and breeding habits is far from adequate. This is remarkable since shrews can be obtained readily in almost any rural district on the mainland of Great Britain. An admirable summary of the earlier work is given by Barrett-Hamilton (1911), and little further information, except that provided by Middleton (1931), has been added. The embryology up to the formation of the geminal layers and the development of the placenta have been described by Hubrecht (1890, 1894). The anatomy of the shrew has been described by Ärnbäck-Christie-Linde (1907), but little attention is paid to the female reproductive organs.