DURING HIS SOJOURN IX THE WESTERN PACIFIC. 565 



is conspicuous on the tail but comparatively inconspicuous on the trunk. The number 

 of rings amounted to about forty. These rings are the despair of the researcher on 

 Lino-uatulids. In the next stage there are at least as many if not more rings 

 (Fig. 32, Plate LVL), whilst in the third stage (Fig. 83, Plate LVI.) there are but 

 twenty-five or si.K. I have one specimen killed in corrosive sublimate and not in alcohol 

 as most of them were, which owing to a fusion of the rings along the median line 

 has at least twice as many rings on one side of the body as on the other. 



The four hooks can just be made out at the anterior end of the second stage, 

 and in Fig. 32 one is shown in profile, but the}' are much more conspicuous in the 

 next stage (Fig. 33, Plate LVL). 



In the second stage the trunk has encroached on the tail which is beginning 

 to swell out and consequently to disappear. The rings are beginning to widen out 

 or possibly two or three of the annulations of the younger forms go to build up 

 a single one in the older stages. This process has commenced in the stage we are now 

 dealing with. Its length is o mm. and its greatest breadth is 1'3 mm. 



The mature and twisted forms were crowded with the long coiled oviducts twisting 

 and looping in every direction. The skin was stretched, thin and transparent. The 

 ova are minute and their number prodigious. With the aid of a haemacytometer I 

 calculated that there must be at least 3000 to the cubic millimetre, a number which 

 gives some 825,000 ova in a medium sized adult. There are of course many sources of 

 error in this method of calculation, but without attaching too great importance to 

 the figures the calculation serves to show how prolific these animals can be. 



List of Ho-sts with their Parasite.s. 



Aetiobatis nai-inari, Euphras. Calliobothrium aetiohatis, n. sp. (p. 541). 



„ Adelohothrium aetiobatidis, n. gen. (p. 545). 



„ „ „ Echinocephalus striatus, Montic. (p. 560). 



Histiophorus, sp. Bothyiocephalus pJicatus, Rud. (p. 540). 



Pimelepturus fuscxw, Cuv. and Val. Distuinina veiitricosuin, var minor, Pal. (p. 540). 



Chelone imhricata, L. Monostomnm trigmocephalum, Rud. (p. 532). 



Varanus indicus, Daud. Palaia varani, n. gen. (p. 548). 



„ „ „ Fhysahptera varani, Par. (p. 560). 



Dipsadomorphus irregularis, Merrem. Phyllobothrium dipsadomorphus, n. sp. (p. 550). 



„ „ „ Physaloptera obttisissima, Molin. (p. 559). 



„ „ „ „ retusa, Rud. (p. 55.9). 



„ „ „ Sclerostomum appendiculatum, Molin. (p. 560). 



„ „ „ Porocephalus tortus, Ship. (p. 563). 



Carpopliuga van-wycki. Coelodela hmiria, n. gen. (p. 552). 



Dioniedea e.iulans, L. Prostliecocotyle diontedeae, n. sp. Fuhrmann (p. 557). 



„ „ „ Gnathostoma sliipleyi, n. sp. Stossich (p. 560). 



The Zoological Labouatory, December 1899. 



Cambridge. 



7.5—2 



