FREE-LIVING NEMATODES 21 



is wide, and one-third as wide as long, occur in the straight uterus. Toward its 

 blind end the narrow, tapering ovary is one-fourth as wide as the body. The tail 

 of the male is conoid in such a fashion that at a distance from the anus equal to 

 four times the anal body diameter it has a width equal to one-fourth the anal 

 body width; thence it tapers very gradually to the terminus, whose width is con- 

 siderably less than that of the spicula. The slender, uniform, acute spicula are 

 one and three-fourths times as long as the anal body diameter. Theejaculatory 

 duct and vas deferens are one-fourth as wide as the body. Apparently there are 

 two tapering testes, but the end of the posterior one was not definitely seen; it 

 appeared, however, to be eight to twelve body widths in front of the anus. 

 Spermatocytes occur in single file near the end of the anterior testicle. 



Habitat; remarks. Bay, Cape Royds. One female and three males in a 

 somewhat shrunken state. 



13. Monhystera antarctica, n. sp. The cephalic setae are very minute and diffi- 

 cult to see. Six excessively minute forward pointing papillae occur, one on each 

 lip. Apparently the pharynx is tra- 

 versed near its middle by a trans- 

 verse ridge, and this is the reason I ^&\ !- 2 2.7 2.9 3.7 

 why it appears in optical section 

 as if armed with two teeth. From 

 the anus, the posterior lip of which 

 is elevated, the rather prominent, chitinized rectum leads inward. Anal glands 

 are present. The rather large and conspicuous nuclei of the intestinal cells are 

 arranged about a body-width apart. The terminus of the tail is one-fourth as 

 wide as the base. The broadly saccate caudal glands, of which two are larger than 

 the third, are arranged in close tandem in the anterior half of the tail; their 

 ampullae are distinct. The lateral fields are one-half as wide as the body. At a 

 distance behind the base of the neck equal to four times the width of the body 

 there is frequently to be seen in the female a large cell, one-half as wide as the 

 body, with a prominent nucleus. This cell occurs in females only. Though its 

 connections have not been definitely made out, it sometimes seems to empty 

 through a pore a little in its rear. The straight uterus, five to six times as long 

 as the body is wide, contains elongated eggs, as long as the bodj r diameter, and 

 half as wide as long. The cylindroid ovary contains ova arranged in double file- 

 irregularly so toward the blind end. 



The tail of the male is a little stouter than that of his mate. The rather frail, 

 slender, uniform, sub-acute spicula, one and one-half to one and three-fourths 

 times as long as the anal body-diameter, lie with their proximae dorsal to the body 

 axis. The single accessory piece, parallel to the distal third of the spicula, and 

 then bending back in a thumb-shaped apophysis, lies with its proximal end oppo- 

 site the body axis. On the tail there are very faint inconspicuous setose papillae 

 one ventro-submedian on each side, at the end of the anterior fourth, and two or 

 three sub-ventral just behind the middle of the tail. The ejaculatory duct is one- 

 fourth to one-third, the vas deferens and tapering testis one-half, as wide as the 

 body. 



Habitat ; remarks. Bay, Cape Royds. Numerous slightly shrunken specimens. 



