Comparison of the Preputial Glands in the Alexandrine,The Wild,and the Domestic Norway Rat. ∗

Abstract

Summary

1. The domestic Norway rat, the animal commonly used in laboratories throughout the world, has much smaller preputial glands than does its wild ancestor.

2. The preputial glands are definitely larger in the wild Alexandrine than in the wild Norway.

3. In all 3 forms, the glands are larger in females than in males.

4. The preputial glands and the adrenals seem to show the same growth relationships in the three forms.