50 



"TERRA NOVA" EXPEDITION. 



characteristic feature in a stained specimen of this worm is a series of about fifteen 

 strong bands of muscular fibres which run down the ventral aspect of the worm. They 

 are continuous from segment to segment. 



Apart from the number of the testes, this form appears to be similar to that 

 recorded by Fuhrmann in 1908 under the name Tetrahothrius pelecani (End., 1819), a 

 binomial abbreviation for Taenia pelecani aquilae Rud. The names Taenia heterosoma 

 and T. sulae fuscae had previously been given by Baird (as nomina nuda) to specimens 

 in the British Museum, which both Monticelli and Fuhrmann, on re-examination, 

 have pronounced to be identical with T. pelecani (Rud.)* 



31. Tetrahothrius nelsoni, Leip. and Atk. (PL IV, fig. 25.) 



Tetrahothrius nelsoni, Leiper and Atkinson, Proc. Zool. Soc, 1914, p. 226. 



Fragments only. Head absent. Testes 6 to 8, aggregated at the side of the segment remote 

 from the cirrus. 



Host. — Sooty Albatros or Hutton's Albatros ( Phoehetria -pal pehvata) ; intestine. 



External Appearance. — Only fragments of the strobila were obtained. The 

 anterior portions are white, the more mature segments grey and almost transparent. 



Segments. — The figure, represents the posterior end of a fragment, where the 

 segments measure 2 mm. transversely and 0 " 4 mm. in length. The hinder lateral 

 borders of each segment overlap the succeeding segment considerably. The staining 

 is diffuse. The genital cloaca (PI. IV, fig. 25, a) is large and thick -walled ; it is always 

 on the same side of the strobila and opens directly on the side. The cirrus (r) 

 measures 0 " 32 mm. x 0-20 mm. From it there proceeds across the segment a very 

 slightly coiled vas deferens (b). The vagina (r) runs an erratic course just behind the 

 vas deferens to almost the middle of the segment, where it turns backwards to end 

 in a large dilatation which varies considerably in the different segments. The contents 

 give a chromatin staining and appear to be spermatozoa. Immediately in front of this 

 is a large ovarian mass measuring 0*15 mm. in its greatest diameter. The testes (t), 

 which number from six to eight, are large, measuring 0"09 mm., and they are 

 aggregated together in a small area on the side of the segment remote from the 

 genital opening. Two narrow excretory canals run down either side ; they are external 

 to the testes and internal to the genital openings. The musculature is poorly marked. 



32. Tetrahothrius creani, Leip. and Atk. (PI. IV, figs. 26, 27.) 



Tetrahothrius creani, Leiper and Atkinson, Proc. Zool. Soc, 1914, p. 225. 



Strobila 4*5 cm. Head 0'84 mm. broad, carrying four suckers but no rostellum. Testes numerous. 

 Yolk-gland large. Cirrus 0 - 06mm. 



Host. — This Cestode was obtained from the small intestine of (Estrelata trinitatis 

 and (E. arminjoniana. These two Petrels in all probability are only one species, the 



• ; ' See Fuhrmann, " Die Cestoden der Vogel," Zool. Jahrh. Suppl. x, 1909, p. 34, note 5. 



