67 



(lie intestine, which unite into a single iiieriue tube, this 

 continuing Uft thick-walled vagina to open at a vulvar orifice, 

 guarded by two prominent transverse lips, a short distance 

 lit. I to u. s 111111.) anterior to the anal orifice, the vulva being 

 thus relatively more anterior than in 0. megaiyphlon. The 

 fully formed ova (Fig. 1) are ellipsoid in shape, usually 

 slightly flatter on one side than on the opposite, and range 

 from 145 x 62 to 170 x 85 inicrom. in size (from measure- 

 ments of a do/en or more, obtained from several females). 

 The shells are smooth, delicate, simple, somewhat pliant, 

 and colorless; the vitelline substance yellow and granular; and 

 with development a colorless, finely granular embryo takes 

 its place. It is to lie remarked further that the writer found 

 several large females among the preserved material which 

 contained well-formed larval worms in their interiors, these 

 showing the general structural features of the adults. From 

 one example as many as five of these larva 1 were dragged in 

 the dissection. It is not known whether these may not have 

 developed within the parent from the ova after death of the 

 worm (but this is suspected Ix-cause developed ova and free 

 larvse were in no instance found together in any of the female 

 worms) or whether the worm is ovoviviparous. 



In the male the two tubular testes are disposed as the ovi- 

 ducts in the female, terminating in a sperm sac. The spicule 

 (Figs. 4, 7 and 8) is single, long, and often double-curved, 

 the distal curve directed dorsally (is sometimes straight). 

 The cuticular tip of the tail (Fig. 4) of the male is straighter 

 than that of O. mfgatyphlon, its sides infolded. It is supported 

 ventrally by a median intracuticul'ar spine which ends in 

 four small prominences on the ventral side of the tip of the 

 tail, and which shows in the median line of its base a second, 

 smaller spine, bipartite at its free end. At the base of the 

 latter, just back of the cloacal margin, there are on each side 

 three small papillir, the largest next the small median spine, 

 the other two diminishing in size. The posterior lip of the 

 cloaca is bilobed, the anterior trilobed, the median lobe the 

 largest. 



