668 
Joumal of Agricultural Research 
Vol. XXVIII, No. 7 
Craterostomum. 
1. Length 9 mm. or more; internal leaf crown consisting of not more than 16 
elements; oesophagus over 500/* long; vulva 1.27 mm. or more from tip 
of tail-- C. acuticaudatum. 
Length not over 8 mm.; internal leaf crown consisting of 18 or more elements; 
oesophagus not over 400/* long; vulva not more than 1.1 mm. from tip 
of tail_2. 
2. Females 8 mm. long; internal leaf crown consisting of 24-25 elements; anus 
425-535/*; vulva 905-1100/* from tip of tail_ C. mucronatum . 
Females*1-5.5 mm. long; internal leaf crown consisting of 18 elements; anus 
250-270/*, vulva 530-570/*, from tip of tail_ C. tenuicauda. 
Cylindropharynx. 
1. Worms more than 12 mm. long; length of mouth capsule more than 3 J times 
its greatest width; no genital appendages__ C. rhodesiensis. 
Worms less than 12 mm. long; length of mouth capsule not greater than 3 J 
times the greatest width; genital appendages present_2. 
2. Length of mouth capsule from 3 to 3i times its greatest width; genital 
cone long (up to 400/*), extending considerably beyond margin of bursa; 
vulva of female not more than 750/*, anus not more than 200/* from tip of 
tail_ C. brevicauda . 
Length of mouth capsule less than 3 times its greatest breadth; genital cone 
short, not extending beyond margin of bursa; vulva of female more than 
750/*, anus more than 200/* from tip of tail_3. 
3. Worms not over 7 mm. long; length of mouth capsule more than twice its 
greatest width; extremity of lateral branch of dorsal ray undivided or 
with only a very small projection; appendages a simple pair of stout, 
finger-shaped processes_ C. longicauda . 
Worms over 7 mm. in length; length of mouth capsule less than twice its 
greatest width; extremity of lateral branch of dorsal ray deeply bi¬ 
furcated; appendages elaborate structures on genital cone and on der¬ 
mal collar___ C. ornata. 
Cylicostomum sensu lato. 
Ihle (2) has divided the large number of species previously placed under Cylicos¬ 
tomum Railliet into seven groups, to five of which he gives the rank of subgenera. 
I prefer to raise these to genera and to give the two remaining groups generic 
names, believing that this will simplify matters. For the Montgomery group of 
Ihle I propose the name Gyclicotoichus, and for his Brevicapsulatum group the 
name Cylicobrachytus. The latter group contains only two species; further 
study may show that they do not belong in the same genus, but until that time 
confusion will be avoided by placing the group in a position corresponding with 
that of the other groups which were made by Ihle. 
1. Dorsal and ventral walls of mouth capsule much higher (that is, longer in 
the direction of the long axis of the worm) than lateral walls > Cylicotoichui . 
Mouth capsule radially symmetrical (that is, wall of equal height through¬ 
out, or without great difference in height). (See C . brevicapsulatum) _>_2. 
2. Mouth capsule extremely short (may be as high as 13-14/* in C. prionodes ); 
elements of internal leaf crown either inconspicuous or wanting. 
Cylicobrachitus. 
Mouth capsule not extremely short (may be as little as 17/* high in C. 
labratum) _3. 
3. Posterior end of female strongly bent dorsally, with a swelling before the 
vulva, the tail in lateral view resembling a human foot-- Cylicocercus . 
Posterior end of female straight or slightly bent dorsally_4. 
