436 cobb: new nematode genera 



preservation is inserted near the end of each description. In 

 most cases the formulae given represent an average derived from 

 the measurement of several adult individuals. 



By the use of suggestive conventional signs the formula is 

 made to convey considerable additional information. Thus the 

 following formula 



35 

 T 1.5 ^7.5il8.5 -50^;... .?.?-•.?..» 1.8 mm. 



1^° iV5"" '2:4"^""0"' 4-5 2.5 



indicates that: 



The cuticle is traversed by rather coarse transverse striae/ 

 which are resolvable into rows of dot-like markings/ and is 

 traversed longitudinally by wings, — one on each side of either 

 lateral line.^ The head bears lips, each of which is armed with 

 two papillae. There are ten cephalic setae, — two of unequal 

 size on each submedian line, and one on each lateral line. The 

 tubular phaiynx is armed with a spear, which is bulbous at 

 the base. Spiral amphids are present.^ The excretory pore 

 is located just in front of the nerve-ring. ^ The oesophagus 

 bears two bulbs: a median bulb half as wide as the corre- 

 sponding portion of the neck, and a cardiac bulb well filling the 

 base of the neck.^ The tail end is armed with caudal glands,^ 

 The two ovaries are outstretched in opposite directions and 

 occupy 35 per cent of the length of the body.^ 



1. Xiphinema americanum, n.g., n.sp. 



Papillae minute. Anterior three- 



1.7 irnn. fourths of the spear about as 



thick as cuticle; posterior two- 



"^"q ^VX ^' ™* fifths twice as thick. Spear bulb 



about one-fourth as wide as neck. 



1 Formula line of coarse dots. Fine dots mean fine striae; plain line, no striae. 



2 Dots above and below formula line between 2nd and 3rd terms. 



3 Short lines above and below formula line between 2nd and 3rd terms. 



* Indicated in conventional sketch at left of formula. 

 ^ Oblique line in front of nerve-ring measurement. 



^ Underscoring the 2nd and 3rd diametral measurements, thus indicating the 

 presence of a bulb at that point. Length of mark indicates size of bulb. 

 ^ Mark at right hand end of formula line. 



* Dashes before and after 50, and 35 used as "exponent." 



Note. Absence of any particular mark indicates the absence of that particular 

 feature, so far as at present known. 



