UNCINAKIA. 



165 



Fig. 93. Fig, 94. 



teeth; toward the inner free border the ventral wall bears on each side of the median line chitinoTJS 

 structures or, teeth often recurved in shape of hooks; the inner dorsal wall may also bear teeth. 

 Type, Uncinaria vulpis Friilich, 1789. 



This is an extremely importaut genus from a medical standpoint as it contains a 

 parasite ( U. duodenalis) which causes a serious disease in man, and two parasites 

 ( U. vulpis and U. stenocephalus) which cause serious trouble in young dogs. 



Lucas found live specimens of worms of this genus in a 3 mouths old fur seal 

 which had starved to death. 



15. UNCINARIA sp. 



(Figs. 93-96.) 



Diagnosis. — Body white. Buccal capsule apparently with a single pair of rather wea,k anterior 

 ventral recurved teeth, and with posterior ventral chitiuous lamellae. 



Male: 6.5™'" long; caudal bursa very similar to that of U. duodenalis, spicules very slender, 

 equal, 0.5'""' long. 



Female: 12'"'" long; tail acuminate; vulva slightly posterior to the middle of the body. Eggs 

 ellipticall24 to 132 /i by 84 to 88 //. 



Habitat: Intestine of fur seal {Callorhinus iirsinua) Bering Sea. Type: U.S.N.M., No. 2815. 



Our material of this form does not permit a detailed study of the 

 mouth, and on this account we hesitate to place the worm specifically. 



No other species of Uncinaria is known for 

 marine mammals. 



The few specimens which Lucas collected certainly 

 could have been of no importance in the economy of the 

 host, but as Uncinaria is a blood sucker of the worst type, 

 and as allied species produce serious troubles in man and 

 dogs, analogy would imply that a heavy infection of the 

 seal would produce similar troubles in that host. Analogy 

 would also imply that the development of the parasite is 

 direct, without intermediate host, and that a crowded con- 

 dition of the rookeries would render an epizootic probable. 

 Under these circumstances the worm might play an impor- 

 tant role in the mortality of the seal pups, more especially 

 if the latter were deprived of food by reason of the killing 

 of their mothers by pelagic sealing. 



SUPPLEMENTARY NOTE TO THE UNCINARIA OF THE FUR 



" SEAL. 



During the season of 1897 Lucas collected a number of 

 specimens of Uncinaria. from seals, and fully verified the 

 prophecy made above. In connection with the study of the 

 new material, the seal commission has requested us to pre- 

 pare a monograph of the genus Uncinaria, discussing the 

 subject from a medical as well as from a zoological ^tand- 

 ^'" ^■^ point. This monograph is now in course of preparation, 



but it is impossible to complete it in time for incorporation in this report, owing to 

 the absence of one of our number from the country. 



