370 PABATYLENCHUS 



There are two or three somewhat ellipsoidal organs, half as wide as the body, 

 about two-thirds as wide as long, located just behind the base of the neck, and 

 closely associated with the beginning of the intestine. These regularly darken 

 in Flemming's solution and are as yet of unknown significance. 



Habitat: Found in soil about the roots of grasses, Devil's Lake, North 

 Dakota, April, 1915;' and Four Mile Run, Falls Church, Va., August, 1922. 

 Flemming's solution to glycerine jelly. In many respects this species closely 

 resembles Tylenchus macrophallus de Man, but differs in the following particu- 

 lars; the spear is somewhat longer and possibly somewhat more robust; the 

 striation is coarser; the body is wider; the tail of nanus compasses twenty 

 annules while that of macrophallus appears to compass about fifty; opposite the 

 spear in nanus there are about twenty-five to thirty annules, while in macro- 

 phallus there appear to be about forty. Should opportunity occur it would 

 perhaps be advisable to re-examine the median oesophageal region of macro- 

 phallus. For the present at least it seems best, unless the undiscovered male 

 of nanus should prove to be extraordinarily like the male of macrophallus, to 

 regard the two species as distinct. Paratylenchus is related to the very well- 

 defined genus Iota, a genus whose numerous representatives typically are 

 minute, very short, very broad, coarsely annuled, rather inflexible nemas 

 found in acid soils, and having the single outstretched female sexual organ 

 emptying through a vulva located very close to the minute, inconspicuous anus 

 and often possessing external coarse retrorse cuticular elements, ridges, scales, 

 spines, fringes, etc., according to the species. There is a number of as yet 

 unpublished species of which it is not easy to make a satisfactory assign- 

 ment as between Iota and Paratylenchus. The unknown males of nanus, if 

 such exist, may be expected to throw more light on the generic relationships. 

 P. nanus may be synonymous with P. bukowinensis Micoletzky, 1922. 



.". .*: , A 1 - . ~ 8 >. . 9 ?- . 0>36 .. 



4- 8 5^i '", 5.6 5.1 3.1 are the measurements of a living specimen 



of P. nanus under slight pressure and therefore a little flattened, and further- 

 more showing a neck-length unaltered by fixation and preservation. 



24. 28. __ 34. Y 92.6<?> 



Paratylenchus ancepsn. sp. 5-3 5.3 /5.J 4.6 3.6 ' " P. anceps so 

 closely resembles P. nanus that only the differences need be here noted. The 

 striae are one micron apart. The optical expression of the wings is a pair of 

 refractive parallel lines whose distance apart is about equal to the width of 

 two annules of the cuticle. The conoid neck becomes convex-conoid at the 

 head, at the front of which the lip region is about four microns wide. The spear 

 guide is six microns long, and the spear about half as long as the neck, the 

 long slender anterior part comprising three-fourths or four-fifths of the whole. 

 The three-lobed, flattish basal bulb of the spear is about one-fourth as wide as 

 the corresponding portion of the neck, that is about four microns wide. The 

 somewhat elongated-pyriform or pineapple-shaped posterior bulb is three- 

 fifths as wide as the base of the neck. The deirids are near the base of the 

 neck. The tail is slightly conoid to the broad, rounded terminus, which is 

 half as wide as the base of the tail. The vulva was about to appear at the 

 same relative position as in P. nanus. In all other respects almost precisely 

 as in P. nanus. 



Habitat: Roots of Umbellularia californica, Riverside, California, 1912. 



