208 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 50. 



Male 3.5 to 4.5 cm. long and 1 to 1.5 mm. thick (fig. 271). The 

 head attains a maximum diameter of about 260 [>.. The pharynx is 

 about 130 \!. long and the lumen is 60 \>. wide. The esophagus at- 

 tains a maximum length of about 4.3 mm. and a maximum thick- 

 ness of 380 [i. The nerve ring is sit- 

 luited near the anterior extremity of 

 the esophagus, about 450 /x from the 

 anterior extremity of the bod3\ The 

 intestine constricts near its posterior 

 extremity to form a piriform rectum 

 Avhich connects with the cloaca. There 

 are two bursal alae, of which the left 

 is over three times as long as the right. 

 The A-entral surface in the bursal re- 

 gion shows the presence in the super- 

 ficial structure of numerous refractive 

 bodies. It also presents the usual 

 rounded oblong cuticular markings of 

 this genus and related genera (fig. 

 272). The spicules are unequal. 

 They present a somewhat irregidar 

 curvature and are narrow with a di- 

 lated proximal extremity. The right 

 one is 1.29 to 1.43 mm. long and the 

 left is 775 to 860 fi long, the short one 

 being shorter and the long one longer 

 than the corresponding spicules in P. 

 muris. There is a chitinous accessory 

 piece in the vicinity of the cloacal 

 aperture. The clocal aperture is on 

 an elevation 860 fi to 1.11 mm. from 

 the posterior extremity of the bod3^ 

 The posterior portion of the body is 

 coiled in one or two turns and is much 

 more rigid than the anterior portion. 

 It terminates in a rounded end from 

 which the bursal alae recurve poste- 

 riorly and then turn anteriorly. 

 There are four pairs of large pre- 

 anal papillae, which are increasingly larger from the one near- 

 est to the cloacal aperture to the one farthest away, and 

 two pairs of large postanal papillae, of which the posterior pair, 

 about midway between the cloacal aperture and the end of the tail, 



imni 



Fig. 271.- 



-rROTOSPlRUKA ASCAROIDEA. 



Male. 



