THE ROUNDWORMS OF DOMESTIC SWINE. 



23 



HOSTS. White-lipped peccary (Tayassu pecan), wild boar (Sus scrofa fera), 

 domestic hog (Sus scrofa domestica). 



LOCATION. Stomach and small intestine. 



LOCALITIES COLLECTED. Brazil; Italy; Germany; Roumania; Madagascar; Indo- 

 China; United States, east, middle, and southwest. (Apparently same range as 

 Arduenna strongylina.) 



As already mentioned, Physoceph- 

 alus sexalatus was first identified 

 as Spiroptera strongylina by Diesing 

 (185 la). Molin (1860b) subse- 

 quently described the specimens 

 under the name Spiroptera sexalata, 

 and the following year Diesing 

 (186 la) placed the species in a new 

 genus Physocephalus, of which it is 

 the type and only species. The 

 specimens studied both by Molin 

 and Diesing were collected by Nat- 

 terer from the white-lipped peccary 

 in Brazil, April 24, 1826, and depos- 

 ited in the Vienna Museum labeled 

 Spiroptera strongylina suis labiati. 



Molin's (1860b) somewhat meager 

 description sums up the salient 

 points (the lateral wings and spiral 

 tail of the male) by which Phy- 

 socephalus sexalatus may be recog- 

 nized. He describes the males as 

 7 mm. long and 2 mm. wide, and 

 the females as 9 to 13 mm. long and 

 3 to 5 mm. wide. The mouth is de- 

 scribed as bilobed, each lobe with a 

 three-cornered margin. Diesing 

 (1861a), although creating a new 

 genus from Molin's species, adds 

 little to our knowledge of its anat- 

 omy. 



It has already been noted that 

 Von Linstow (1879b) has appar- 

 ently mistaken Physocephalus sexa- 

 latus for Arduenna strongylina. 

 His measurements of the spicules 

 (0.72 mm. for the long and 0.26 mm. for the short spicule) are, how- 

 ever, much too short for A. strongylina and also for P. sexalatus. 



Von Drasche (1884a), in his reexamination of Diesing's and Molin's 

 specimens, made a careful study of the bursal papillae and the struc- 



Momm. 



c/. 



FIG. 19. Physocephalus sexalatus. Posterior end 

 of body of male. 6. w., bursal wing; cl., cloaca; 

 1. *p.,long spicule; pr. p., preanal papillae; . 

 sp., short spicule; v. r. c., ventral ridge of the 

 cuticle. X 50. (Original.) 



