78 NORTH AMERICAN 



granules are so prominent as to obscure the cellular structure of the in- 

 testine. From the very slightly elevated and rather inconspicuous anus the 

 rectum, which is hardly as long as the anal body diameter, extends inward 

 and forward. The tail is conoid to the terminus, where it rather suddenly 

 tapers much more rapidly to a very acute point. This rapidly tapering por- 

 tion has a length about equal to one-fourth the anal body diameter, and the 

 diameter at the point where the change in taper begins is about equal to one- 

 fifth of the anal body diameter. The lateral fields appear to be a little more 

 than one-third as wide as the body. The nerve-ring surrounds the oesopha- 

 gus obliquely. The excretory pore is located a little behind the nerve-ring, a 

 little more than half way from the base of the neck to the middle of the 

 median bulb. From the slightly elevated, rather massive vulva the vagina 

 leads inward at right angles to the ventral surface nearly half way across 

 the body, where it joins the two uteri. Apparently the ovaries are out- 

 stretched. A single egg has been seen in one of the uteri. It is about twice 

 as long as the body is wide and about one-third as wide as long. It is thin- 

 shelled and apparently undergoes segmentation before being deposited. 



3.1 13.5 20.5 -M 3 89.1 



2.2 3.6 3.9 4.2 3.2 



The tail of the male is like that of the female in form. From the raised 

 anus it is arcuate-conoid to the terminus, which is concave-conoid and ends 

 in an exceedingly fine slender point. The length of the terminus is about 

 one-third as great as the anal body diameter, while its diameter is about 

 one-fourth as great as the anal body diameter. There are no supplementary 

 organs, nor have any special papillae been seen either in front of the anus 

 or behind it. There is a fairly well developed, but not very prominent bursa, 

 which extends but little beyond the ventral contour at any point. It springs 

 from the submedian lines at a distance as far in front of the anus as the 

 middle of the tail is behind it. The bursa is striated like the cuticle, and its 

 margin is entire; it extends to near the end of the tail. Near the middle 

 of the tail there appears to be a bursal rib on each side, which does not 

 reach to the margin of the bursa. The ejaculatory duct is about one-third 

 as wide as the body. The blind end of the single outstretched testicle lies 

 a short distance behind the base of the neck. 



Habitat : Marsh in black clay with much decayed vegetation, near Im- 

 patiens, Arlington Farm, Virginia. Flemming solution to glycerine. 



RHABDITIS, Dujardin, 1845. 



7i 



1.2 10.8 16.8 '55' 93.8 



25. Rhabditis punctata, n.sp. - 1.8 mm. 



1.2 3.3 4.3 4.9 1.6 



The thin layers of the transparent, naked, colorless cuticle are traversed 

 by transverse striae, which are resolvable with high powers and appear to be 

 resolvable into rows of dots, but there is some doubt about this. The cuticle 



