58 PROCEEDINGS OF THE NATIONAL MUSEUM vol.81 



the union of the fourth and last fifth of the muscular portion of the 

 esophagus. The cervical papillae lie near the posterior end of the 

 muscular esophagus and the excretory pore is slightly farther 

 posterior. 



Male: Length 7.4 to 9.2 mm; width 0.3 to 0.4 mm. The muscu- 

 lar portion of the esophagus is 0.2 to 0.25 mm long, and the glandu- 

 lar portion is 1.43 to 2 mm long. The nerve ring and excretory pore 

 are 0.2 to 0.25 and 0.4 mm, respectively, from the anterior end, 

 The cervical papillae are about midway between these two structures. 

 The tail is 0.28 to 0.35 mm long. The spicules are subequal, but as 

 the two vary independently either the left or right may be the 

 shorter. They are only 0.155 to 0.175 mm long. The left spicule is 

 well cutinized and about 10/x wide near the anterior end. It widens 

 a very little beyond its middle and ends in a moderately sharp point. 

 The right spicule is poorly cutinized and about 13/a wide at its base. 

 Beyond the middle it widens to a maximum of 25/i, then tapers to 

 a sharp point. The usual caudal alae are present and are supported 

 by four pairs of circumcloacal papillae. The inner surface of the 

 alae is decorated with raised longitudinal ridges. There are three 

 papillae on the cephalic cloacal lip, and two pairs of papillae on 

 the caudal lip. Three pairs of papillae are evenly spaced between 

 the cloaca and the tip of the tail. 



Female : Length 9 to 14.2 mm ; width 0.35 to 0.4 mm. The mus- 

 cular esophagus is 0.27 to 0.33 mm long, and the glandular esophagus 

 is 1.7 to 2.8 mm long. The nerve ring and excretory pore are 0.25 

 to 0.28 and 0.3 to 0.45 mm, respectively, from the anterior end. The 

 cervical papillae are about halfway between these two structures. 

 The vulva lies slightly behind the caudal limits of the first third of 

 the body; it is nonprotuberant, and from it the vagina runs caudad 

 for 1.35 mm. The two uteri are convergent. The eggs measure 

 25yx by 42/t. The female tail is 0.33 to 0.5 mm long and ends bluntly. 

 The pores of the caudal glands are situated very near the tip of the 

 tail. 



Hosts. — Leiolopisma latercde and Agkistrodon mokasen. 



Habitat. — Stomach. 



Locality. — Houston, Tex. 



Type sj^ecimen.—U.S.'^.M. Helm. Coll. No. 31711. 



Remarks. — The host distribution of this species seems at present 

 to be rather unusual, since it includes a snake and a lizard. It 

 was this that suggested the specific name squamatae. The parasite 

 was not present, however, in a very high proportion of the hosts 

 examined, and doubtless it will be found in other reptiles of 

 these groups. 



In the structure of the mouth region this species can be distin- 

 guished from P. plirynosoma by the presence of the inner teeth, and 



