THE SEA OTTER IN THE EASTERN PACIFIC OCEAN 273 



of 271 Corynosoma sp. Infestation ranged from 1 to 98 individuals. 

 T. decipiens, totaling 40 individuals, occurred in 5 of the tracts 

 and infestation ranged from 1 to 18. 



A subadult female sea otter v^as found dead at Patten Bay, 

 Montague Island, by Theron Smith on 23 April 1962. The animal 

 v^as estimated to have been dead for 2 or 3 days v^hen it was 

 received for study by Dr. Francis H. Fay. Because death ap- 

 parently resulted from helminth infestation, his study of this 

 animal (No. 27830) is quoted from his letter of 7 August 1962. 



Trematoda: Orthosplanchnus fraterculus. Abundant in gall bladder bile 

 ducts. Extreme fibrosis and near-occlusion of bile ducts was noted in several 

 areas of the liver. 



Microphallus pirum. Abundant in small intestine. 



Cestoda: Diplogonoporus tetrapterus. Several large pseudophyllidean 

 cestodes with double genital pores were present in the small intestine. A few 

 smaller cestodes, closely associated with these, were also present and are 

 believed to be aberrant individuals of the same species. 



Nematoda : Terranova decipiens. Massive infection, mainly of larval worms. 

 These had perforated the stomach in one locality and the duodenum in two. 

 Many were free in the abdominal cavity, together with M. pirum and two 

 species of Corynosoma. In the abdominal cavity there was about 1,000 ml. 

 of bloody fluid with some remnants of food that evidently had oozed out of the 

 intestine by way of the perforations. A group of nematodes was attached 

 to the greater omentum, and several other groups had penetrated the spleen 

 and liver. Extreme inflammation was evident in these sites even in the then 

 decomposed tissues. All mesenteries in both the abdominal and pleural cavities 

 were granular and inflamed. Adhesions were abundant. 



Acanthocephala : Corynosoma sp. At least two species of Corynosoma were 

 abundant in the small intestine." (These were later identified by K. Neiland 

 as C. strumosum and C. macrosomum.) 



It was apparent from the gross pathology that this animal had died as a 

 result of its dense, infiltrating parasite population, but it was not possible to 

 decide on which of the two most pathogenic organisms (M. pirum and T. 

 decipiens) was primarily responsible for causing death. 



External parasites 



Snow (1910, p. 278) examined many sea otters and said of 

 them '*Sea-otters are particularly cleanly animals; I have never 

 found a parasite of any description on them." 



F. H. Fay (letter, 6 April 1964) said: 



We have no records of Anoplura on sea otters, but on the other hand, the 

 number of specimens examined is not great. Both Bob [Rausch] and I feel 

 that Barabash-Nikiforov's record of two specimens of Proechinophthirus 

 fluctus (=Echinophthirus fluctus) on sea otters probably was fortuitous. Ap- 

 parently this is a common ectoparasite of Callorhinus and Eumetopias living 

 in the same area with the otters, and it is not inconceivable that a few would 

 occasionally be picked up by the otters. If it were a common or even uncom- 



