FREE-LIVING NEMATODES 17 



spicuous, elevated vulva, the well developed, tubular, muscular vagina extends 

 inward and obliquely forward. It is about twice as long as the corresponding 

 body-diameter, and about two-thirds as long as the uterus. The eggs are about 

 as long as the body is wide, and three-fourths as wide as long, and have been seen 

 two or three at a time in the uterus. The ovary is of medium size, and tapers so as 

 to become narrow. It contains many ova, arranged single file somewhat irreg- 

 ularly so near the uterus. 



The slender, more or less uniform spicula taper from the middle toward the 

 proximal ends, and present the striking peculiarity of being strongly curved at 

 the distal extremity, forming a hook across which there is a thin, transparent 

 membrane. They are one and three-fourths times as long as the anal body-diam- 

 eter, and are so arranged that their proximal ends appear as if lying to the dorsal 

 side of the body axis. Their yellowish framework is rather strong, and the proxi- 

 mal two-thirds may sometimes be seen to be nearly straight. At the extreme end 

 the spicula have a very minute recurved apiculum or point. Two (?) pairs of 

 ellipsoidal granular unicellular glands (?) occur some distance in front of the 

 spicula. This species has the head of a Monhystera but differs, in having the 

 oesophagus altered in the posterior half, a well developed ventral gland, special 

 lateral cells, hamate spicula without accessory pieces, and the tail with a group 

 of small setae near the middle. 



Habitat; remarks. Cape Royds. The five females and five males examined 

 were in fair condition. 



MONHYSTERA, Bastian, 1865 



The following are characters common to all the species of Monhystera here 

 described. 



Cervical and somatic setae none or scattered and short, except in M. pilosa. Neck 

 conoid, but cylindroid in the posterior half in M. pilosa, and M. meridiana. Tail 

 tapering from the anus or a little in front of it. Oesophagus somewhat cylindroid 

 without swellings of any kind, for the most part about half as wide as the nec'k, 

 but finally three-fifths to three-fourths as wide as the base of the neck. Cardia 

 present, except in M. frigida, hemispherical to cylindroid, and one-fourth to one- 

 half as wide as the base of the neck. Intestine separated from the oesophagus by 

 a collum one-third to one-half as wide as the neck, becoming almost at once about 

 three-fourths as wide as the body, its walls thick and two to four cells in girth, 

 and the lining usually so refractive that the lumen is a rather distinct feature. 

 Granules of the intestinal cells numerous, fine and uniform. Rectum of about 

 the same length as the anal body diameter. Caudal setae none or inconspicuous 

 except in M. pilosa. Lateral fields one-third, more rarely one-half, as wide as the 

 body. Renette unknown except in M. pilosa and M. uniformis. Nerve-ring of 

 medium width, surrounding the oesophagus rather squarely, the nerve cells in its 

 vicinity usually rather diffusely arranged. Vulva small or of medium size and in 

 these species not very conspicuously elevated except in M. uniformis. Vagina one 

 to two times as long as the body is wide, and extending inward and forward. 



7. Monhystera pilosa, n. sp. Striae about 1700. There are numerous long, very 

 slender, flexible cervical and somatic setae, often arranged in pairs, one member of 



