20 



THE ROUNDWORMS OF DOMESTIC SWINE. 



FIG. 16. Arduenna dentata. Median view 

 of cephalic end. ph., pharynx; t. b. c., 

 teeth of the buccal capsule. Enlarged. 

 (After Von Linstow, 1904f, PI. I, flg. 5.) 



strongylina. The specimens were subsequently studied by Molin 

 (1860b), recognized as a new species, and named by him Spiroptera 

 sexalata. Later helminthologists, although accepting Molin's species, 

 have continued to include Dicotyles Idbiatus among the hosts reported 

 for Arduenna strongylina, apparently ignoring the fact that Molin's 

 (1860b) correction of Diesing's (1851a) identification eliminates the 



peccary as a host of Arduenna stron- 

 gylina, since this, species has never 

 been reported in the peccary except by 

 Diesing (1851a). Stossich (1897b) ap- 

 parently considered Dicotyles albiro- 

 stris and D. labiatus as separate species, 

 listing under the former Spiroptera stron- 

 gylina and under the latter the para- 

 sites collected by Nattererfrom the pec- 

 cary and described by Molin (1860b). 

 The stomach appears to be the 

 normal location for Arduenna strongylina; Von Ratz (1899d), how- 

 ever, reports its occurrence in the small intestine. 



Arduenna dentata (Von Linstow, 1904) Railliet and Henry, 1911. 

 Von Linstow's (1904f) description of this species is as follows: 



Cuticula finely annulated. The mouth leads into a pharynx 0.11 mm. long. Ite 

 entrance is armed with a dorsal and a ventral tooth; the mouth is a transverse slit, the 

 border of which shows both an- 

 teriorly and posteriorly, three 

 notches with papillae (fig. 16). 



1 ~ X./ I "\. \ 



The esophagus measures -g-g of the \- 



entire length and presents a spiral 

 musculature. In a young worm 

 14.6 mm. long, the nerve ring 

 surrounds the esophagus 2.64 mm. 

 from the head end, and the excre- 

 tory pore opens at a point situated 

 0.31 mm. behind it. The male 

 (25 mm. long by 0.79 mm. broad) 

 has a closely involuted tail which 

 resembles that of Spiroptera 

 strongylina. The spicules are re- 

 spectively 0.35 and 0.92 mm. long, 

 the shorter one bearing at its end 

 a barb. Immediately anterior of 

 the anus on each side there are four preanal papillae situated close together; behind 

 it there is one papilla. All have long stalks. The anus is surrounded by a broad 

 ring, notched externally; the bursa shows longitudinal rows of oval scales. (Fig. 17). 

 The female grows to a length of 55 mm. with a width of 1.10 mm. The short conical 

 tail is curved over the back; the vulva is placed far behind the middle and divides the 

 body in the ratio of 70 to 23. The eggs are small, thick shelled, and cylindrical, meas- 

 uring 0.039 by 0.017 mm. 



FIG. 17. Arduenna dentata. Bursa of male, ventral view. 

 d., cloaca; I. b. w., left bursal wing; I. sp., long spicule; 

 po. p., postanal papillse; pr. p., preanal papillae; pr. r., 

 perianal ring. Enlarged. (After Von Linstow, 1904f, PL 

 I, fig. 7.) 



