BY N. A. COBB. 397 



the body, and has a length equal to that of the anal body-diameter. 

 The narrow unicellular ventral gland lies just behind the cardiac 

 constriction, and is two to three times as long as the body is wide. 

 Immediately behind it occurs an organ about one-fourth as long, 

 which, however, stains differently. This organ is ventral and 

 contains two large and peculiar nuclei arranged on opposite sides 

 of the ventral line. What is this organ? Before answering 

 let us call attention to two cells near the cardiac bulb in Plectus, 

 another genus of free-living Nematodes. If I am not mistaken 

 the first to see these cells in Plectus intelligently was Joseph. 

 He suggested that they were nerve-cells. They are joined by a 

 commissure, are subventral in position, and are near the ventral 

 gland, which in Plectus, contrary to the general rule, is situated 

 in the neck in front of the cardiac bulb. What I wish to empha- 

 size is the proximity of the ventral gland and these two supposed 

 nerve-cells. In my little Chromadora minor a similar proximity 

 occurs — tw^o cells, which, judging from their situation and struc- 

 ture, may be nerve-cells, are ranged close behind the ventral 

 gland. We may not be wrong, I think, in calling these two 

 cells nerve-cells ; it is with more hesitation that I suggest them 

 to be parts of a sympathetic nervous system, traces of which 

 have hitherto, I believe, escaped observation among Nematodes. 

 The nerve-ring in C. minor is placed at an angle of forty -five 

 degrees with the body axis. The lateral fields are one-fourth as 

 wide as the body. The tail is conoid to the terminus, which is 

 one-third as wide as the base of the tail and presents a small 

 outlet for the secretion of the three caudal glands. These latter 

 seem to be confined to the tail. The slightly projecting vulva 

 leads into a vagina reaching half-way across the body. Each of 

 the uteri often contains a roundish egg, which is deposited before 

 segmentation begins. The ovaries reach fully three-fourths of the 

 way back to the vulva, and each contains about a dozen developing 

 ova arranged in single file. 



•6 8-3 14- — M 89- _, , -i • -,., , « , 



1:3 — 27 ao 3-8 2-7 I'lS"^'^- The male tail is like that of the 



female, except that the anus projects slightly. Hairs occur both 

 in front of and behind the anus. Notable for their larger size are 



