"The Baculum in Microtine Rodents" by Sydney Anderson is a scientific publication written in the mid-20th century. This work focuses on the anatomy of the baculum—a bone found in the penis of many placental mammals—and its implications in determining the taxonomy and relationships among various species of microtine rodents, particularly within the genus "Microtus". The text includes detailed anatomical descriptions, methodologies used for specimen collection, and discussions around the significance of the baculum in understanding species variation and evolution. At the start of the publication, Anderson introduces the importance of the baculum in microtine rodents, emphasizing its utility in taxonomic studies when combined with other anatomical features. The opening sets the stage for an intricate examination of previous research on the baculum from different species and varieties of rodents, including "Microtus", "Synaptomys", and "Clethrionomys". The author outlines the methods for preserving and examining the baculum, providing insights into the anatomical orientation and the variations observed across different specimens, thereby establishing a foundation for the detailed accounts that follow in the subsequent chapters. (This is an automatically generated summary.)