Korp?i. 13:2 



many genera, but others show great modifications from this pattern. 

 There may be fusion of pairs of lips giving rise to three lips or 

 reduction of some and enlargement of others. >/hen there are six lips, 

 the submedial lips carry three papillae each, one apical and two sub- 

 lateral in position. The two lateral lips carry two papillae, but 

 along with the alteration or modification in lip structure there 

 may also go modification in the number and arrangement of the papillae. 

 The lips not infrequently bear, or are surrounded by, various cuticu- 

 lar protuberances. In certain terrestrial nematodes, such as Acrobeles, 

 peculiar structures termed probolae , three or six in number, project 

 fon-jard; they vary from simple rounded, conical, or forked eminences 

 to branched projections resembling antlers. VJhen six are present, they 

 are arranged in two circlets of three each. 



In the region of each lateral lip, but behind the anterior face, there 

 is a pair of sense organs very characteristic of nematodes, the amphids 

 (Plate I, Hig. 3, A). The openings of the amphids are most conspicuous 

 and best developed in the Aphasmidia, but are also present as minute 

 pores in the Phasmidia. The amphidial openings of the Aphasmidia are 

 cuticular depressions of three general shapes: cyathiform (Plate II, 

 Fig. 1, A, B), spiral (Plate II, Fig. 1, D), and circular (Plate II, 

 Fig. 1, C), The amphids consist of a gland and nerve ending's and are 

 presumably chemo receptors. In most plant parasitic forms, the pore- 

 like opening of the amphid cannot be seen except by a study of en face 

 preparations. ' 



The -general body surface may be smooth, but very often is marked by a 

 regi.ilar series of transverse striations (Plate I, Fig. 1, 2, T). These 

 striations are often interrupted by the lateral fields (Plate I, Fig. 1, 

 K and Fig. k, A) which are quite prominent in some forms but are rather 

 inconspicuous in others. In addition to the transverse striae, there 

 may also be longitudinal striations (Plate I, Fig. U, B). In the tail 

 region of males of phasmidia, extentions of the cuticle often form lat- 

 eral alae ( caudal bursa ; Plate I, Fig. 2, Y) which are employed in 

 copulation and generally bear genital papillae (Plate IV,' Fig. 1, G). 



Another type of cuticular marking is termed punctation . Punctations 

 are minute dots or ovals which nay occur in transverse or longitudinal 

 rox-Js and often are arranged in patterns. 



Near the posterior end of many nematodes there occurs a pair of cuticu- 

 lar pouches resembling the amohids. These are called ohasmids (Plate I, 

 Fig. 1, 2, V) and are probably sensory in function. They are located 

 in the lateral fields, generally in the tail region or just above it. 

 Sach consists of a short duct opening on the surface of the cuticle, 

 and leading inward to a small unicellular gland. Often a surface pa- 

 pilla is associated with the phasmids. In some cas>=s the gland and 

 duct may degenerate, leaving ©nly the surface papillae as evidence of 

 theii" former existance. 



