268 MR. H. A. BAYLIS AND LT.-COL. CLAYTON LANE ON 



The head-bulb (text-figs. 16-18) is, relatively to the size of 

 the worm, very small. It consists of two hemispheres separated 

 laterally but continuous doi'sally and ventrally, and is thus 

 comparable with that of very young examples of T. tiara. The 

 sti-iations are very well-marked. 



The oesophagus occupies from one-twelfth to one-eighth of the 

 total length. The cervical sacs (text-figs. 16 ik 17) are relatively 

 short, extending through, roughly, the first quarter of the length 

 of the oesophagus. 



There is nothing in the number, shape, or arrangement of the 

 caudal papillae of the male (text-fig. 19; PI. IV. fig. 14) to dis- 

 tinguish this form from T. tiara. The preanal " sucker-like 

 organ," referred to by v. Linstow (1904 a), appears to us to have 

 been simply the terminal portion of the intestine, seen in optical 

 transverse or oblique section by transparency through the body- 

 wall. We can find no superficial sucker-like organ on the ventral 

 surface. 



The vulva is situated at about one-third of the body-length 

 from the posterior end. The vagina is short, and opens at right 

 angles into the uterus. The latter has two branches, which usually 

 proceed at once from the termination of the vagina to run 

 a,nteriorly and posteriorly respectively. In a young specimen 

 from Tropidonotus asperrimus (text-fig. 20), the muscular vagina 

 appeared to be very short, and continued as a common uterine 

 tube for a short distance before the divergence of the two 

 branches. 



Specific Diagnosis. 



Tanqua anomala (v. Linst.). 



Head-bulb divided in the adult into two swellings, situated 

 dorsally and ventrally, each containing two ballonets. Head not 

 retractile witliin the cuticular collar. Vulva at about the 

 junction of the middle and last thirds of the bod3^ Utei'us 

 wibli two opposed branches. 



Habitat: stomach of serai-aquatic snakes {Tropidonotus, etc.). 



For list of hosts, see p. 271. 



3. Tanqua DiADEMA * Baylis, 1916. (Text-figs. 21-23; PI. III. 

 fig. 15; PI. IV. fig. 16.) 



Tanqua diadema Baylis (1916, p. 227 ; text-figs, 3, 4). 



This species, which is now redescribed with some slight correc- 

 tions, is readily distinguished from the preceding form from 

 snakes by the prepuce-like fold of cuticle within which the 

 head-bulb a,nd lips can be completely retracted. The cuticle, 

 especially anteriorly, is often very thick and wrinkled, reminding 

 one of the condition frequent in Gnathostoma. 



* For specific diagnosis, see p. 271. 



