Eitdopardsifrs from Cldchens. 249 



part being 17 to '11 ft long by 17 to 27 fx wide (except for its 

 posterior end, where it overlaps the oesophagus and reaches a 

 width of 31: fi). Though it is not apparent from the range of 

 sizes just given for the pharynx, the hinder part is slightly 

 longer than the front part in 12 out of the 16 speciiuens. The 

 well-developed cuticular lining of the pharynx is produced at the 

 junction of its anterior and posterior portions so as to project 

 irregularly forwards (cf. 0. mansuiii. Ransom, 1904, p. 15). 

 Sometimes in O. par varum (cf. Fig. 18) there is also an inward 

 and anteriorly directed projection from the wall of the anterior 

 portion of the pharynx, which does not appear to be represented 

 in 0. mcmsoiii. The oesophagus has the club-shape comparable 

 to 0. mansoni, but is sliorter than in that species, never reaching 

 over 1.3 mm. in length, and usually being only about 1.13 mm. 

 long. 



Male. — 9.2 to 14.5 mm. long, by .2'6 to .33 nun. thick, i.e., 

 rather shorter and thinner than 0. mansoni. The tail (Fig. 19) 

 is very sharply curved ventrally, much more so than in 0. 

 mansoni, and ends in a somewhat sharp point, the tip of the 

 tail not being recurved, as in that species. No membranes are 

 present. The cloacal opening is 230 to 300 /j-.from the tip of 

 the tail, wh'ch is distinctly less than in 0. mansoni. Five 

 pairs of anal papillae are present, 3 preanal arranged in two 

 lines, slightly diverging from back to front, though not as 

 much so as in 0. mansoni. Two post-anal pairs are found, one 

 close behind the cloacal opening and one a short distance behind 

 that again. I have not been able to distinguish any other 

 papillae sini'lar to those lying one on either side of the cloaca 

 in 0. mansoni. There are two spicules, one (Fig. 19, l.s.) long 

 and thin, the other (Fig 19, s.s.) short, thick, and boat-shaped 

 in its distal portion, which acts as a guide for the longer spicule. 

 The latter is 3.4 to 4.1 mm. long and 11 to 12.7 /i. thick along its 

 length, swelling out to 24 or 30 //, at its open base. The short 

 spicule is 180 to 210 (in one case 240) /<. long by a maximum 

 diameter of 27 to 42 /i. These spicules differ in length and 

 thickness from 0. mansoni. 



Female. — 13.5 to 20 mm. (generally al)out 15 uini.) long by 

 .27 to .39 mm. thick, i.e., thinner than 0. mansoni. The anus 

 (Fig. 20) is 390 ft to 440 (rarely) f,., and vulva .78 to 1.07 mm. 



