ECOLOGY AND BIOLOGY OF THE PACIFIC WALRUS 



235 



March-April 1976 were screened against Leptospira pomona monovalent 

 antigen in slide agglutination tests. All results were negative. Fifty-four of the 

 same serum samples were tested for antibodies to San Miguel Sea Lion Virus 

 infection, also with negative results (A.W. Smith and D. G. Ritter, personal 

 communication) . 



Miscellaneous Nonspecific Conditions 



Aneurysm 



An adult female, taken in outer Bristol Bay had a large, sterile cyst (20 cm in 

 diameter) on the ventral surface of the spleen (Fig. 134). The cyst was turgid, 

 filled with a mixture of fresh and necrotic blood, and its walls were about 3 mm 

 thick. The histological character of this cyst indicated that it was an aneurysm, a 

 localized dilatation of one of the splenic arteries, probably of long standing 

 (R. A. Dieterich, personal communication). An aneurysm of this size could be 

 expected to cause some pain through pressure and, perhaps some erosion of 

 adjacent organs. 



Fig. 134. Arterial aneurism (left) in the spleen of an adult female Pacific walrus. 

 The cyst, about 20 cm in diameter, was filled with blood. Card at lower right is 

 127 X 76 mm. (Photo by F. H. Fay) 



Uterine Tumors 



Brooks (1954) mentioned the finding of intra-uterine "cysts of unknown 

 nature" that "appeared capable of occluding the lumen of the affected horns" in 

 2 of about 40 uteri examined by him at Little Diomede Island in the spring of 



