PLATE 1 
A. — Cephalobus subelongatus Cobb: head end sublateral view; amph, amphid. 
B. —Same; head end: m inc, main incision between main lips. 
C. —Same; one main sub ventral lip with the two papillae separated by a flat 
incision; m lb, main lip; subv ppl, sub ventral papilla; lat ppl, lateral papilla 
behind the amphid. 
D. —Same; cardiac region of the body; els, cells which apparently belong to the 
excretory apparatus; nrv r, nerve ring; p ex, excretory pore; ren, renette or 
ventral gland; t p, transparent tissue of the cardiac region of the intestine; valv, 
the ribbed valvulae of the valvular apparatus; valv el 2, second group of three 
rod-like valvular elements; valv el 3, third group of three valvular elements of 
same form as those of group two. 
E. —Same; front view of the head end; amph, amphid; sub p, submedial papilla; 
lat p, lateral papilla. 
F. —Same; cross section through the middle region of the body; cl int, intes¬ 
tinal cell; mem, cutinized membrane around intestinal cavity; gon, gonad; subl 
al, sublateral wing. 
G. —Same; tail end of a male; dil an, dilatator muscle of anus; gub, guberna- 
culum; rtr sp, retractor spiculi; ptr. sp, protractor spiculi; sp, spiculum; 1-7, 
papillae of the male tail end; some double, as 6a, 6b, 7a, 7b. 
H. —Same; ventral view of the male tail end; gub, gubernaculum; retr, retractor 
spiculi; 1-6, papillae of the male tail end; number 6 is double, number 7 can not 
be seen as situated on the dorsal side. . 
I. J, K, L, and M.—Same; sketches of different male tail ends to show the varia¬ 
tions in the number and position of the papillae, of which some are double. 
N.—Same; a lateral view of the spiculum and the gubernaculum; eph, cepha- 
lated proximal end of spiculum; gub, gubernaculum; md s r, median strengthening 
rib of spiculum; vnt br, branch of the ventral rib. 
