148 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 2 



There is a shallow buccal cavity which is followed by the esophagus. 

 The anterior end of the esophagus is cuticularized, and the inner mar- 

 gins of the esophageal walls are extended anteriorly and outward to 

 form a buccal cavity rim. In an optical section of the lateral surface of 

 the cephalic region, the buccal cavity rim may be seen as a toothlike 

 projection arising from the wall of the esophagus. 



The nerve ring encircles the anterior end of the esophagus from 

 0.175 to 0.210 (average 0.186) mm. in the male and from 0.196 to 

 0.224 (average 0.200) mm. in the female from the anterior end of the 

 body. The excretory pore is slightly prebulbar in both sexes. The dis- 

 tance the pore is located from the anterior end of the body varies from 

 1.08 to 1.51 mm. in the male and from 1.28 to 1.70 mm. in the female. 

 The excretory pore and canals are similar to those described for the 

 other species of Alaeuris. The esophagus is elongated, slender and mus- 

 cular throughout its length. It terminates posteriorly in a subspherical 

 bulb. The entire esophagus varies in length from 1.12 to 1.37 (average 

 1.26) mm. The ratio of esophagus to body length is about two fifths in 

 the male and one fourth in the female. The anterior part of the esopha- 

 gus which is in contact with the buccal cavity is bluntly rounded and 

 heavily cuticularized. Posteriorly the esophagus connects with the en- 

 larged bulblike region of the intestine. 



Male: The reproductive organs are similar to those described for 

 the other species of Alaeuris. There are three pairs of genital papillae 

 (figs. 19 and 20). Two of the pairs are circumcloacal and the third is 

 caudal in position. The precloacal papillae are sessile, but situated on 

 prominent body eminences. Dorsal and slightly lateral to these papillae 

 are two stalks which project posteriorly beyond the limits of the pa- 

 pillae. These structures are the cloacal lips which are similar in appear- 

 ance to the papillae-bearing stalks, but a careful examination of all of 

 the specimens studied was made and no papillae were distinguished. The 

 second pair of circumcloacal papillae is located on long peduncles which 

 arise from the posterior body wall. They are lateral to the accessory 

 piece. The third pair of papillae is situated on relatively stout peduncles 

 which arise from the tail. 



The caudal alae (fig. 20) are smooth. They extend laterally almost 

 the body width, but ventrally only a short distance, almost to the dorsal 

 side of the accessory piece. 



There is a single sharply pointed spicule (fig. 15). The length varies 

 from 0.689 to 0.792 mm., with an average of 0.739 mm. Near the 



