4 PROCEEDINGS OF THE NATIONAL MUSEUM vou eff 



structure of the esophagus which is without a bulb. The fact that 

 the members of this genus have a pre-anal sucker and a bursa-like 

 tail in the male has been generally considered sufficient ground to 

 warrant their inclusion in the Heterakidae, and this classification 

 is followed by most helminthologists. 



ASCARIDIA ANSERIS, new species 



Male. — 32 mm. long by 600[x wide. Cuticle finely striated. Head, 

 separated from rest of body, l72[x wide, measured near the base. 

 Esophagus simple, 1.75 mm. long by 285[i, in maximum width. 

 Nerve ring about 350a from cephalic extremity. Sucker circular, 

 138[ji. by 130[JL, its posterior margin being located at a distance of 

 172[jL from the anus and at about 700yL from the posterior extermity. 

 On one side of the body there are 14 papillae of which 5 are pre-anal 

 and § post-anal (fig. 1). The first three papillae are ventral in 

 position and are arranged in a row on each side of the sucker the 

 most cephalad papilla being anterior to the sucker, the middle one 

 lying in the region of sucker and the last papilla being posterior to 

 the sucker. Of the next two papillae, one is ventral and one is lateral 

 {11). In the following group of three papillae one is lateral {21) and 

 two appear to have a ventral position. Of the remaining 6 papillae 

 four are lateral {31^ Jfl^ 51., 61) and two ventral. The distances 

 between the tips of the first four lateral papillae are almost equal 

 and greater than the distance between the last two lateral papillae. 



The papillae on the other side of the worm are only 13 in number, 

 the corresponding first lateral papilla being absent. The remaining 

 papillae, though corresponding in number to those on the opposite 

 side, show in some respects a different arrangement ; the third lateral 

 papilla appears to be absent, being replaced by a ventral papilla {x). 

 The fourth, fifth, and sixth lateral papillae correspond to those on 

 the opposite side. 



The spicules nearly equal, 820[jl and 827tJL long, respectively, and 

 terminate bluntly. The tip of the tail in my specimen is broken off, 

 as can be seen from the jagged posterior extremity in the illustration. 



Female. — Unlmown. 



Host. — Anser domesticus. 



Location. — Small intestine. 



Localittj. — Hanoi (Tonkin) Indo-China. 



Type specimen. — U. S. National Museum Helminthological Collec- 

 tions No. 26011. 



Variation in number and in position of papillae in the genus 

 Ascarklia is apparently not uncommon. In Ascaridia columbae, 

 as recently figured by Bay lis and Daubney (1922), the papillae show 

 considerable variation in position. It is not improbable that the 



