PARASITIC WORMS— LEIPER AND ATKINSON. 



47 



The margins both of the head and of the orifices of the suckers are rounded (PI. V. figs. 

 32, 33). 



Segments. — The segments figured (Fig. 34) are about the 221st and 222nd. The 

 shape of the hinder segments usually varies considerably, but in general conformation 

 the remaining segments are the same. A typical segment measures 1*35 mm. trans- 

 versely, but is only 0*47 mm. long. The genital pore opens marginally near the 

 anterior border of the segment. There is a slender, elongate, unarmed and sometimes 

 pyriform cirrus, measuring 0 " 14 mm. The vas deferens makes its way as a straight 

 uncoiled lube to the centre of the segment, where it ends in a, slight dilatation. 

 Caudad, bit! in dose proximity to this, is a narrower tube, the vagina, which runs to 

 the middle of the segment, ending in a small punctate mass which possibly represents 

 the shell-gland. The testes are rounded and are arranged very definitely in two sets, 

 divided by the vas deferens and vagina. The set on the side of the pore usually 

 numbers seven to eight, and that on the opposite side 17 or 18. The total number of 

 testes is 24 to 25, of which the majority (from 17 to 18) occupy that side of the 

 segment distant from the cirrus. They are situated internally to the excretory canals. 

 The segments do not overlap in any way, and their lateral borders are rounded. A 

 fair number of chalk-bodies are present. Even in the most caudal segments there are 

 no eggs, and the uterus is not fully developed. 



The infection of the Rorqual was evidently a recent and a, very heavy one, 

 This species has been made the type of a new genus Oriana near to Diplobothrium, 

 a, preoccupied genus, in I he family Phyllobothriidae. 



Oki.er CYCLOPHYLLIDEA. 

 Fam. TETRA B< )THRIIDAE. 



Tetrabothrius, Rud.. 18 1!). 

 28. Tetrabothrius heteroclitus, Dies. 



Host. — Great Grey Shearwater (Ptiffi.it/is cincrciis) ; small intestine. 



External ( 'haracters. — These Cestodes are exceedingly long and slender and are 

 from L0 cm. to L3 cm. long. The segments are fairly uniform in shape, but towards 

 the caudal end they become broader from side to side and decrease comparatively in 

 depth. They are broader in front than behind and each overlaps the succeeding 

 segment for a short portion. Their hinder ends are carried out as sharp points beyond 

 the margins of the succeeding segments. The worms were in a tangled mass in the 

 intestine, and were thus exceedingly difficult to separate. 



Head.- The head is shaped like a truncated cone bluntly rounded off. From the 

 sides hang the loin- suckers with well-developed auricular appendages. The lips of the 

 suckers are broad and folded inwards. The cavities widen posteriorly. The suckers 

 do not appear on the anterior surface of the head. 



The head, which is succeeded bv a fairly long and simple neck, measures 0'37 mm. 



