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THE FUR SEALS OF THE PRIHILOF ISLANDS. 



Fig. 1. 



Summary. — The ascaride of the Alaskan fur seal is si)ecifically iiulentical witli an 

 ascaride found in Phoca largha and Eumetopias stelleri in the same locality, and with 

 the form described by Krabbe in 1<S78 as Ascaris decipiens from the stomach of Phoca 

 vituUna, P. (jroenlandica, J', hispida {=P.foetida), P. barbata {=Erignathus barbatus), 



Trichcchns rosmartis ( = Odobcnns rosmarus),Oystopliora 

 crisfata and several undetermined marine mammals. 

 The species from Phoca barbata, described by Cobb in 

 1888 as Ascaris bnlbosa, does not appear to differ essen- 

 tially from this form. Baird's (1853) Ascaris similis, 

 from the stomach of an Antarctic seal (see p. 147), and 

 his Ascaris hicolor, described in 1868 as parasitic in 

 the stoma(!h of Trichechvs rosmarvs (see p. 142), are 

 possibly also identical with Krabbe's si)ecies. The 

 parasite has a wide geographical distribution, and is 

 acquired by seals through eating fish. In detail the history of the worm is as follows: 

 Historical review. — Kegarding A. simHis, see page 147; for A. bicolor, see 

 page 139. 



Krabbe (1878, pp. 45-47, resume, pp. 11, 12) described this species from material 

 collected in Greenland by various persons (see p. 101)) from Phoca groenlandica, P. bar- 

 bata {^Urignathns barbattcs), P. hispida {= P.foetida), 

 P. vitulina, Cijstophora cristata, and Trichechns ros- 

 marns {^= Odobcnns rosmarus). Besides these hosts, 

 from whic-h the worms were collected, in all in seven- 

 teen cises, specimens were found 

 three times in unnamed seals from 

 Faroe (by Miiller), Iceland (by 

 Steincke), and Greenland (by An- 

 dersen). It was also found once in 

 Phoca vitulina off the west coast of 

 Schleswig. Tlie parasite often oc- 

 curs with A. osculata in the same 

 host, and for Imth of these species 

 the stomach is a more common hab- 

 itat than the intestine. In one case 

 a "couple of hundred" worms were 

 present, of which one-third were 

 males. The males attained 45""" in length, the females GO""'. 



The lips ai'O nearly alike, without intermediate lips; each lip 

 bears (fig. 1) a broad, rounded anterior double lobe, separated from 

 the basal portion of the lip by a lateral concave border. The inner 

 surface of the margin of the anterior lobe is provided with a den- 

 tigerous ridge, arranged in a tripi)ly curved line. Of the six pairs of 

 ])ostanal papillae in the male (tig. 2) three jtiiirs of conical papdlae 

 are near the tip, and increase in size from the tip forward, so that 

 the third pair is the largest; nearer the anus are three pairs of 

 smaller papillae; anterolateral of the anus is situated 071 each side a row of conical 

 papillae, which increase in size from the first to the seventh or eighth. 



i... 



Fig. 2. 



