128 



THE FUR SEALS OF THE PRIBILOF ISLANDS. 



SuMMAKY.— A. typica (Diesing) belongs to Dujardin's subgenus AnisaMs (type, 

 A. Dussumierii). It was described in 1860 by Diesing as type of a supposed new genus 

 Gonocephalus, but Krabbe (1878) and Drasche (1883) showed that the structure upon 

 which the genus was based was not a part of the worm. Krabbe described it as a 

 new species, A. conocephalus ; Drasche placed it in the genus Peritrc(.cheUus; Leidy 

 misdetermined specimens from the Pacific Ocean as '^Ascaris simplex Eudolphl," and 



Fig. 31. 



Tig. 30. 



Fig. 32. 



it is not at all impossible that Dujardin'a "A. simplex 'E>nAo\^h.V^= A. Dusswmierii is 

 identical with this form (see p. 161). In detail the history of the species is as follows: 

 Historical ebvibw. — For a discussion of Dujardin's form see page 161. Diesing 

 (1860, p. 669) described a parasite (fig. 30) as Gonocephalus typicus, type and only 

 species of a supposed new genus, as follows : 



Familia XII. Conocophalidea. Character generis uald simul familiae. 



XLI. Gonocephalus Diesing. 



Corpus elongatum teretiiiBculutn. Caput conicum, limbo suo postico crenulato a corpore distante, 

 retractile. Os in apice capitis. Exjtremitas candalis maris semispiralis, siibtiis excavata, papilla 



