PARASITIC WORMS LEIPER AND ATKINSON. 47 



The margins both of rhc head ami of tin- orifices of the suckers arc rounded (PI. V, tigs. 

 :\-2. 33). 



^1-i/iin'iit.t. The segments figured (Fig. 34) are about the 221st ami J2'2ul. The 

 shape nf the hinder segments usually varies considerably, hut in general conformation 

 the remaining segments are the same. A typical segment measures l - :35miu. trans- 

 \er--elv. luit is onlv 0'47 mm. long. The genital pore opens marginally near the 

 anterior lionlrr of The segment. There is a slender, elongate, unarmed and sometimes 

 pvriforin cirrus, measuring 1 -1 mm. The vas deferens makes its way as a straight 

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

 ('alidad, but inclose 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 

 I lie shell-gland. The testes are nmnded and are arranged very definitely in two sets, 

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

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

 lestes is -J4 to - 7 ,i, 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 anv wav, and their lateral borders are rounded. A 

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

 no eiigs. and the uterus is not fullv developed. 



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



This species has been made the t vpe of a new genus Orinnn near to Diplobothrium, 

 a preoccupied genus, in the family Phvllobothriidae. 



ORDER CYCLOPHYLLIDEA. 

 FAM. TETRABOTHRIIDAE. 



T^trnbatln-iiix, Paid., 1819. 

 _'s. Tetrabothrius heteroclitus, Dies. 



I lxt. Great Grey Shearwater (Pujfinus i-hifrt'itx) : small intestine. 



External Characters. These Cestodes are exceedingly long and slender and are 

 li'om I Ocm. to l:l 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 tin- a short portion. Their hinder ends are carried out as sharp points beyond 

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

 intestine, and were thus exceedingly difficult to separate. 



//'in/. The head is shaped like a truncated cone bluntlv rounded off. From the 

 sides hang the four suckers with well-developed auricular appendages. The lip.s of the, 

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

 d<> not appear on the anterior surface of the head. 



The head, which is succeeded by a I'airlv long and simple neck, measures (. l ':!7 mm. 



