PARASITIC WORMS — LEIPER AND ATKINSON. 



40 



in D. perfoliatum. They were found by Mr. D. (A. Lillie. in a seal killed near Coulman 

 Island, Lat. 74° S. approximately, and a- similar set was seen at Hut Point in 

 Lat. 77° 45' S. 



External Appearance. — The worms are from 3cm. to Gem. long, the average 

 length being about 5 cm. The strobila is shaped like an Indian club, being narrow in 

 front, broadest behind the middle, and tapering slightly to the hinder end. The colour 

 is a yellowish white. The head, around the suckers, contains a very characteristic 

 scarlet pigment. 



Ilnnl, —The head measures 1*64 mm. from before backwards, and 1 '44 mm. from 

 side to side in its broadest part. Anteriorly there are two deep suckers lying ventrally 

 and dorsally. The sucker measures 0'52 mm. internally, 1 mm. externally, and 

 1 '45 mm. from before backwards. Its hinder part is surrounded by a free edge. A 

 bright scarlet pigment-band on the outer side of the fold surrounding the sucker is 

 very characteristic. It only encroaches partially on the inner side ami measures 

 ()'l I mm. at its broadest part. 



Segments. — The segments immediately succeed the head without the interposition 

 of a, neck. They vary in size, measuring 2 mm. transversely at the head-end, 5 mm. 

 at the broadest portion, and 3 mm. at the tail-end. The segment described is from 

 near the head-end of the worm. The dorso-ventral measurement is 2' 14 mm. The 

 segment consists of a central portion, measuring 0'32mm. from before backwards, 

 and two lateral portions. There is marked imbrication of the segments, as in 

 D. perfoliatum. The genital openings are central and are placed partly on the anterior 

 surface of the overlapping edge. The cirrus is fairly large, measuring 0'41 mm. in 

 length and 0"1 1 mm. in breadth ; it is anterior to the vagina, which is a, slender tube 

 measuring 0*24 mm. in length and 0'02 mm. in width. The testes are numerous and 

 extend out into the lateral portions of the segment. The uterus is also extensive, the 

 eggs, which measure 0*025 mm., being present in the later segments to near the 

 periphery. Two winding excretory canals run down either side of the segment close 

 to the junction oi I lie central and lateral portions. The musculature is not so well 

 marked as in IK perfoliatum. The longitudinal bands are small and are not continuous 

 over a large number of segments. The fibres are small and insignificant. The circular 

 fibres are better marked. 



25. Plerocercoid larva, sp. inc. (PI. V, figs. 39, 42.) 



A few larvae, apparently of Bothriocephalid Tapeworms, were found encysted 

 under the mucous coat of the pyloric processes of the gut of Trematomus bernacchii. 

 It is impossible to associate them with any particular species, but there is every 

 probability that they are the young stages of one or other of the species of Dihothrio- 

 cephalus or Diphyllobothrium found in the Seals. 



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