THE NEMATODE FAMILY GNATH OSTOMTD Jil. 



269 



The head-bulb (text-fig. 21) is divided into two hemiRpheres, 

 as in T. aiiomala. Tlie lips (text-fig. 21) are rather large 

 relatively to the head-bullj. The cesophagus occupies about 

 one-tenth of the total leiigtli. The cervical sacs are short. 



In the male the tail (PI. III. fig. 15; PI. lY. fig. 16) has 

 rather wide ahe. The caudal papilla} are similar in number and 

 arrangement to those of the other species. The second pair from 

 the tip of the tail, however, are relatively small in some specimens, 

 and do not always show the basal swelling to a very marked 

 extent. The spicules are suddenly narrowed at the extremity to 

 form a little, conical, smooth tip (text-fig. 22). 



Text-figure 21. Text-figure 22. 



Text-fig. 21. — Tanqna dicxJeiiia. The head, with the cuticuhiv sheath removed ; 



dorsal (or ventral) view. 

 Text-fig-. 22. — Tanq?(a d'tademn. Tormina] portion of spicule. 



Text-figure 23. 



OS mm. 



Tanqna diadema. Female genital organs. (Mature specimen.) 



In the female the tail is tapering and sharply pointed. The 

 vulva opens in the middle third of the body. The vagina (text- 

 fig. 23) is short and thick. It opens at right angles into the 

 uterus, the two branches of which at once pass off in opposite 

 directions, without further subdivision. 



