ECOLOGY AND BIOLOGY OF THE PACIFIC WALRUS 177 



Fig. 109. Oblique ventrolateral view of the hindquarters of an adult male 

 Pacific walrus in June at Round Island: P, penile aperture; R, midventral raphe; T, 

 bilateral bulge of the semi-scrotal testes. (Photo by K. W. Kenyon) 



is the ovary. Each ovary is enclosed in a relatively tight-fitting bursa with a 

 small (about 2x1 cm) oval aperture, the bursal slit, near its uterine end. The 

 funnel of the oviduct, with longitudinal ranks of fimbriae, surrounds all but the 

 most anterior edge of the bursal slit and is much smaller and less elaborate than 

 those of either phocids or otariids. From the funnel, the oviduct passes in a 

 sinuous course around the posterior curvature of the bursa, then along its lateral 

 surface to the ovarian ligament, which it penetrates to enter the short fallopian 

 tube and the uterus through a minute papilla. In at least 10 females whose 

 ovarian bursae I examined in detail, this was consistently the course of the 

 oviduct; that is, it was not "short and straight," as described by Burne 

 (1909:737). 



In the ligaments about the ovarian bursa, I frequently found one to three 

 fluid-filled cysts up to 2 cm in diameter. Cysts of this kind also occur frequently 

 in other pinnipeds and occasionally in man and other mammals, where they 

 have been identified as enlargements of rudimentary mesonephric and para- 

 mesonephric ducts (Gardner et al. 1948). Their occurrence in the walruses 

 seemed unrelated to reproductive status, except that I found none in sexually 

 immature animals. The cause and function of these cysts are unknown (H. W. 

 Mossman, personal communication). 



