18 



in length and 0.044 to 0.048 mm. in transverse diameter. 

 The measurements of the head structures follow: transverse 

 diameter of circular lip, 0.1 mm.; of chitinous ring underlying 

 this lip, 0.06 mm. ; diameter of oral opening, 0.02 to 0.03 mm. ; 

 length of collar about neck of worm, 0.26 mm., transverse 

 diameter of same, 0.28 mm.; length of esophagus, 0.7 mm., 

 with a transverse diameter in its posterior portion, 0.2 mm.; 

 lateral cervical papilla 0.17 mm. posterior to this collar. 



The single male example included in the material measures 

 14.5 mm. long, and at middle of length 0.45 mm. in thickness. 

 Tail obtusely conical, ending in a bilobed bursa (with indis- 

 tinct ventral lobe), not much wider in lateral (0.6 mm.) than 

 in dorsoventral measurement (0.4 mm.). Dorsal ray deeply 

 bipartite, its divisions widely curving from one another, each 

 with a single, simple, small branch near root; dorsomedian 

 ray simple, arising at base of dorsal ray; lateral and ventro- 

 lateral rays from a common base, the former divided; ventral 

 ray divided. Just above the level of the cloaca a small ray 

 or papilla from the body wall. Cloaca 0.2 mm. from tip of 

 tail. Two equal, long, pliant spicules, 1.3 mm. long and 

 protruded in the specimen examined 0.9 mm. Anterior end 

 of male as in female. 



Comparison of these features with those of known cesopha- 

 gostomes would indicate a close relation with (E. inflatum 

 (A. Schneider), if not entire identity. In many respects it 

 agrees well with Linstow's Strongylus aculeatus (Wurttemb. 

 Jahresb., 1879, p. 333) from a macaque monkey, but the 

 mouth parts are distinctly different (in the presence of the 

 cervical collar and in the absence of the two lateral teeth in 

 the mouth); and both anteriorly and in the details of the male 

 tail it differs distinctly from Molin's (Esophagostoma pachy- 

 cephalum (II sottordine degli Acrofalli, p. 450) of a cerco- 

 pithecus. While the host in this case is far removed from 

 the ordinary host of (E. inflatum (large intestine of beef), 

 the correspondence of structure is so great as to make the 

 writer unwilling to regard it as constituting a separate species. 

 This detail of description is here inserted for reference, inas- 



