. 464) 



THE MONONCHS 



at both extremities. The adjacent figure (34) depicts the tail end of a male found 

 in Hawaii about the roots of sugar-cane. The general resemblance to the male as- 

 signed by Biitschli to M. truncatus Bastian is very striking, yet 

 the differences in detail are also pronounced. The number of 

 supplementary organs is 16 instead of about 20, and the organs 

 themselves relatively shorter and more plump. The spicula and 

 their accessory pieces have the same general proportions and size. 

 The tail also has the same form and proportions, but the termi- 

 nal portion is more slender in the Hawaiian specimen, and the 

 distribution of the papillae thereon is decidedly different, as will 

 be seen by comparing figures 15 and 34. Male mononchs are so 

 rare that the amount of variation that may exist in a given 

 species is a nearly unknown quantity, so that it is not exactly 

 easy to make intelligent comparisons between the males in 

 these two cases. The Hawaiian male is supposed to be the 

 male of M. longicaudatus, the only one that has ever been 

 seen. It is interesting to note that when the spicula become 

 long and slender the accessory pieces also become long and 

 slender, but maintain their general form and are bifurcated at 

 the distal end. Fig. 33 (on the previous page) and fig. 34. It is 

 a curious fact that this, the only male of M. longicaudatus 

 ever seen among the many thousands examined, should have 

 come from soil, since longicaudatus is much less common in 

 soil than in water. 



2ia. M. dentatus, n. sp. This representative of a new subgenus is especially 

 interesting as a guide to speculation concerning the relationship of Mononchus to 



27. '62' 14 95. 



1.1 mm 



3.6 2.8 3.3 3.3 1.9 



other genera. The scattered denticles are 

 paralleled in certain marine nemas. The 

 arcuate tail is conoid from the raised anus. 

 The rather blunt terminus is about one- 

 fourth as wide as the base of the tail. There 

 is a pair of ventrally submedian, innervated 

 papillae a little in front of the middle of 

 the tail. The amphid is sometimes more elongated than shown in the illustrations. 

 Description of a young female, from roots of orange trees, Bahia, Brazil. Fig. 35. 

 For 21b, M. recessus, and 21c, M. decurrens, see Appendix, p. 184. 



22. M. punctatus, n. sp. This species is proposed for the reception of the 



specimen described by Brakenhoff under the name M. papillatus Bastian, which 



appears to differ from 2.6 ? 25. 65' 26 93. 



any mononch hitherto ^2 ? ? 3~75 ? 



described in that the shells of 

 the eggs are echinulate. It is 

 placed in the subgenus Pri- 

 onchulus, though with some 

 doubt, principally because both 

 the description and the figure 

 of Brakenhoff show the pres- 

 ence of denticles on the ven- 

 tral rib of the pharynx. The 

 author says: "Hier findet sich 

 namlich cine, in der Mitte (und an den 2 Seiten) fein gezahnelte Leiste. Diese 



