258 • MR. II. A. BAYLIS AND LT.-COL. CLAYTON LANE ON * 



It is a curious fact that the number of uterine brandies in 

 this genus appears to be in direct correlation with tlie number 

 of external divisions of the head-bulb. In the forms parasitic 

 in snakes, where the liead-bulb is composed of two portions 

 only, the nterus has two branches ; while in T. tiara, where there 

 are, in the adult, four swellings on the head-bulb, there are also 

 four uterine branches. 



Nothing is known of the development or life-history of any 

 of the species of Tanqua. The hosts, so far as is known, are all 

 carnivorous reptiles, and belong to semi-aquatic genera ; and it 

 is not unnatural to suspect that there may be an intermediate 

 host which lives in or near fi'esh water, and is eaten by the final 

 host. « 



Generic Diagnosis. 



Tanqua* R. Blanchard. 



Gnathostominae : head-bulb coarsely striated transversely, un- 

 armed, divided externally into two or four swellings containing 

 the ballonets. Body unarmed. Each lip with five teeth, inter- 

 locking with those of the other lip. Cuticle behind the head-bulb 

 forms a more or less pronounced collar or invagination. Tail of 

 male with well-developed alse and eight pairs of papilke, of which 

 the largest are the third, fifth, and seventh. The fourth and 

 sixth paii's small, ventral, and forming a circum-anal group. The 

 larger papillae have a large swelling before the finger-shaped 

 termination. Spicules equal, tubular, rasp-like, with smooth 

 tip. Vulva in posterior half of body ; vagina running forward 

 from the opening. Uterus consists of two opposed branches, or 

 of three anterior branches and one posterior. Eggs oval, with 

 thin shell ornamented with fine granulations. Embryos not 

 fully-formed at the time of laying. 



Habitat : stomach of semi-aquatic lizards (Yaranidse) and 

 semi-aquatic snakes {Tropidonoi,us, etc.). 



Genotype : T. tiara (v. Linst., 1879). 



Key to Species of Tanqua 



A. Head -bulb witli four swellings. Uterus with four 



branches, three anterior and one posterior. Parasitic 



in semi-aquatic lizards (VaranidaB) T. tiara (p. 259). 



B. Head-bulb with two swellings. Uterus with two branches, 



opposed. Parasitic in semi-aquatic snakes. 



a. Head retractile T. diadema (p. 268). 



h. Head not retractile T. anomala (p. 264). 



* For measurements, see Table III., p. 270. 

 f For doubtful species, see p. 271. 



