DURING HIS SOJOURN IN THE WESTERN PACIFIC. 



547 



ylk gid 



The sections of the mature proglottides that I cut showed the reproductive organs 



fairly well, the spermatozoa were already 

 fully formed and the vas-deferens was 

 in parts very much swollen with them. 

 The testes were large and scattered fairly 

 uniformly over the proglottis. Their 

 ducts united into two chief ducts on 

 each side, which ultimately unite. The 

 penis was not armed. The ovary lies 

 quite at the anterior end of the pro- 

 glottis, close to it was a finger-shaped 

 gland which I take to be the shell-gland. 

 The deeply staining yolk glands are un- 

 usually pron)inent; they are so arranged 

 as to form half cylinders, represented in 

 section by two crescents which surround 

 the other generative organs. The ducts 

 of those of each side unite and form a 

 wide canal which with the similar duct 

 from the other side of the body opens 

 into the duct which leads from the ovary 

 into the uterus. 



Fig. C. Adelobothrium aetiobatidh, n. g. Diagram of 

 reproductive system. 



(J gen. pore, male genital pore, ? qeii. pori 

 pore, (jlds. glands round vagina, ov. ovary 



gland, t€s. testis, »(. 

 ylk. gld. yolk gland. 



female genital 

 sh. gld. shell 



uterus, ves. sem. vesieula seminalis. 



Adelobothrium aetiohatidis, n. gen. et sp. 



Head with rostellum imbedded in tissues of host but bearing no hooks. Behind 

 the head the neck swells out into an enormous ruff-like collar. This bears on its 

 anterior face four very small suckers which seem to take little or no part in the 

 attachment of the worm to its host. The section of the body anteriorly is circular 

 and so is that of the anterior end of each proglottis, but the ripe proglottides tend 

 to be flattened in their middle regions. Each proglottis is produced backward into a 

 very prominent ridge which ensheaths the succeeding proglottis to a varying extent 

 according to their age. 



The genital pores are unilateral and irregular, but groups of three opening on 

 one side followed by groups of three opening on the other, succeed one another with 

 some regularity in certain regions. 



Both dorsal and ventral, longitudinal, water-vascular canals persist, and anteriorly 

 the longitudinal muscles are in unusually powerful and distinct bundles. 



Species. Adelobothrium aetiobatidis with the characters of the genus. 



Habitat. The intestine of Aetiobatis narinari Euphrasen, amongst the folds of 

 the spiral valve. The host was taken at Lifu, Loyalty Islands. 



w. V. 



73 



