The hamsters all possess cheek-pouches, which are, however, absent in many of the following genera.
The cheeks are provided with large pouches opening externally.
Hence the gonads are found on the manubrium in Anthomedusae generally; on the base of the manubrium, or under the gastral pouches, or in both these situations (Octorchidae), or under the radial canals, in Trachomedusae; under the gastral pouches or radial canals, in Narcomedusae.
Among other important genera Cricetomys and Eosaccomys (both African) stand apart by the possession of cheek-pouches: C. gambianus being a very large species.
In the female the ovary is a large unpaired organ from the anterior end of which arise two oviducts, and connected with the latter are a pair of large so-called copulatory pouches, which perhaps act as receptacula seminis.