138 



THE FUR SEALS OF THE PRIBILOF ISLANDS. 



The adult females (fig. 40) vary in length from 37 to 44""", in breadth from 1.5 to 

 2"'"', and are attenuated slightly toward each extremity. The vulva, according to 

 Diesing, lies distal of the middle of the body; according to Drasche, about in the 

 middle. In one of our specimens, 44""' long, the vulva was found 20"'"' from the head. 

 The vagina measured e"™ long, the body of the uterus 8""", the horns 8'"'". The eggs 

 (flg. 48) are globulat, 40 /x to 56 fi, and undergo segmentation in the uterus. The anus 

 is about 0.26'"'" from the tip of the conical tail. 



Nomenclature. — The specific term typica has priority, while Diesing's (1850) name 

 Peritrachelius can not be applied to this form, either as generic or subgeneric name, 

 even should, as Drasche thinks, A. typica be generically (or subgenerically) related to 

 Peritrachelius insignis, since A. typica belongs in Dujardin's (1845) subgenus AnisaMs, 

 of which we make it the type. 



Young specimens of Ascaris typica. — Besides the adults described above, TJ.S.N.M. 

 No. 5015 contains numerous specimens (figs. 49-52) of young ascarides corresponding 



Fig. 50. 



Fig. 51. 



to the young forms of A. decipiens described on page 116. They measure 15 to 22'"'" 

 in length by 0.25 to 0.34""" in breadth, and present the characters usually given for 

 "A. capsularia." The ventral tooth is slightly more prominent than in the young of 

 A. decipiens. Specimens may be found with the larval cuticle, or with this cuticle 

 partially discarded. 



We do not hesitate to look upon these as the young of A. typica and to assume that 

 the host becomes infected by eating fish. 



4. ASCARIS BICOLOR Baird, 1868 [nee Rudolphi, 1793]. 



(Pigs. 53-57.) 



Sp. inq. 



f 1809, Ascaris simplex, BudolpM, see pages 120-126. 



1868, Ascaris hicolor Baird [ueo Rudolphi, 1793], Proo. Zool. Soc. London, p. 71, figs. A-C— Murie, 



1868, Proc. Zool. Soc. London, pages 67-71.— Von Linstow, 1878, Compendium der Helmin- 



thologie, p. 42.— Stossioh, 1896, Boll. Soc. adiiatica Sci. uat. 'Trieste, XVII, p. 67. 



Diagnosis. — Intermediate lips absent; lateral cervical alae absent; lips distinct, prominent, 



rounded, of moderate size, more distinct and larger than in A. simplex, and provided with a dentiger- 



ous ridge. Body cylindrical, attenuated anteriorly (but less so than A. simplex), of a brownish color, 



except at the anterior extremity which is white; the posterior extremity is sometimes red. Cuticle 



