462 



gland terminates in a small ellipsoidal ampulla which empties 

 through the porus excretorius a little behind the nerve- ring (9-5%). 

 The nerve-ring is as wide as the oesophagus and oblique. The tail 

 is concave-conoid from in front of the inconspicuous anus. The 

 terminus is slightly swollen, having a diameter nearly one half as 

 great as the anal diameter and giving exit to the secretion of the 

 anal glands. The female sexual organs are double and symmetri- 

 cally reflexed, occupying at least 35% of the length of the body. 

 From the inconspicuous vulva the vagina leads to the two-parted 

 uterus, either branch of which contains two eggs each about three 

 fourths as wide as the body and four or five times as long as wide. 



!f f, ^"'^ — ,•" ^.l 1-85 mm. Tail unlike that of the female inasmuch as 

 it diminishes rapidly from a little in front of the anus, especially on 

 the ventral side, — the anterior eighth being thus somewhat conoid. 

 Then follows a slight but sudden swelling most prominent on the 

 ventral surface. Thence to the slightly swollen terminus the tail is 

 uniformly one third as wide as at the anus. The two equal slender 

 spicula, almost half as long as the tail, are of nearly uniform size 

 throughout and arcuate only in the distal third and there but 

 slightly. Proximse slightly swollen. Of the three pairs of papillse 

 one is pre-anal, opposite the arcuate portion of the spicula, and the 

 remaining two are post-anal, the smaller being near the anus and 

 the larger being situated in the depression in front of the swelling 

 on the tail. 



ffab. — Adults of both sexes are common in sand on the beaches 

 of Arabia during the winter months. 



O. EXiLis, Cobb.* Female unknown. 



il_^_J|^-^^I-^'^ 216 mm. The distinctly compressed head, suc- 

 ceeding to a conoid neck, is somewhat rounded in front and bears 

 ten setse, one dorsal, one ventral, and four double submedian. The 

 food, passing the six triangular flap-like lips, enters a pharynx 

 nearly as wide as deep. The two smaller pharyngeal teeth reach 

 half way to the mouth, being only two thirds as long as the 



* Cobb, " The Differentiator." Sydney, 1889. 



