212 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 50. 



275. 27G. 



Figs. 275, 276.— Peotospikxjra ascaeoidea. 275, Terminal genitalia of female. 276, Egg. 



Genus PHYSALOPTERA Rudolphi, 1819. 



Generic diagnosis. — Spirurinac (p. 199) : Mouth with two equal 

 lips, each with three papilhic and armed Vvith teeth. Variable 

 cuticular expansions posterior of the lips. Caudal bursa formed by 

 a cuticular border of the deeply excavated posterior extremity and 

 with this border continuous anteriorly across the ventral surface and 

 connecting the lateral borders. Many caudal papillae of which four 

 pairs, two preanal and two postanal, are stalked. Two unequal or 

 subequal spicules. Two ovaries. Vulva toward the anterior por- 

 tion of the body. Oviparous. Parasitic in the digestive canal, 

 especially the stomach, of mammals, birds, and reptiles. 



Type-species. — Physaloptera clausa Rudolphi, 1819. 



ANALYTICAL KEY TO SPECIES OF PHYSALOPTERA. 



1. Mnle 6 lum. loiijj. Female unknown Pliysalopfcra spirula, -p. 213. 



Male, where known, 9 mm. Ions or longer. Females known 2. 



2. Females 7 to 13 mm. long. Males unknown Physaloptera citilli, p. 213. 



Females 14 ram. long or longer. Males known 3. 



3. Males over 20 mm. long. Females over 33 mm. long. 



Physaloptera muris-hrasiliensis, p. 213. 

 Males less than 20 mm. long. Females less than 33 mm. long 4. 



4. Males 15 mm. long or longer and with a pair of postanal papillae close to 



the tip of the tail. Eggs spherical, IG to 22 fi in diameter. 



Physaloptera sciuri, p. 217. 



Males less than 15 mm. long; or if that long, with the last pair of postanal 



papillae relatively remote from the tip of the tail. Eggs elliptical and 



with a maximum diameter exceeding 22 n 5. 



5. ISIales 15 mm. long or longer. Females over 20 mm. long. 



Physaloptera circularis, p. 215. 

 Males less than 10 mm. long. Females less than 20 mm. long 6. 



6. Bursa margin with numerous scallops. Of the sessile caudal papillae there 



are 1 large unpaired preanal and 1 large unpaired postanal, and 2 pairs of 

 postanal Physaloptera ruwcnzorii, p. 216. 



