56 



"TERRA NOVA " EXPEDITION. 



the Bay of Islands, New Zealand. The specimens are minute, pearly white and almost 

 spherical bodies, measuring, on the average, 1 ' 02 mm. long. The greatest breadth 

 is 0 • 96 mm. 



On the outer aspect of the anterior half of the body are four large fleshy suckers 

 surrounding a depression from which four rostella emerge. The borders of the suckers 

 project beyond the body at their posterior limits. The muscular fibres of the suckers 

 give the walls an appearance of coarse striation. 



The rostella are long and slender, slightly bulbous at their distal ends, and well 

 armed with series of backwardly curved hooks. They measure 0*45 mm. in length, 

 0 - 06mm. in breadth at their distal ends, and 0 ' 04 mm. at their proximal ends. In 

 vertical series the hooks number eleven rows, and in horizontal series eight rows. 



From the posterior end of each hook-bearing rostellum, a cylindrical portion, 

 possibly muscular, proceeds backwards and is surrounded by a short kidney-shaped sac. 

 These sacs are 0 ' 37 mm. long and 0 • 14 mm. broad. 



Into the posterior half of the body a broad but short " abdomen " or tail is 

 countersunk, and the tail shows a slight median depression. There are always a large 

 number of chalk-bodies contained in the interior. The surface of the body is smooth 

 and the whole cyst appears to be enclosed in a delicate transparent capsule probably 

 secreted by the host. 



Abothros, Welch, 1876. 

 38. Abothros cqreharias, Welch, L876. (PI. Y, fig. 36'.) 



This worm, a larval form, was obtained from the stomach of a small shark 

 ( Carcharias sp.) caught in 1910 at the Island of S. Trinidad (Stat. 37). It consists of 

 a clubbed anterior portion, and a longer and more slender tail "telescoped" into the 

 fore-body somewhat after the manner of the "abdomen" of Hemiurus. The total 

 length is 21 mm., the anterior portion measures 7 "3 mm., and the tail-end is 13 "7 mm. 

 long. The tail-end is in part protrusible. 



The body is surmounted anteriorly by four slender rostella armed with hooks. 

 The length of the rostellum is 0'7 mm. ; the breadth, which is uniform, being 0'12 mm. 

 The vertical number of hooks is twenty-seven, and the horizontal number is eight 

 in each row. The hooks are sharply down-curved, sharp-pointed, and w ith a broad 

 base; they measure 0'03 mm. from tip to base. There is a striking diminution in the 

 size of the hooks of the proximal rows. There is a well-marked sac for each rostellum. 

 To each are attached long bundles of muscular fibres which run back, to become inserted 

 into the line of attachment of the abdominal portion of the bod}'. The excretory canals 

 run down into the tail-portion. The skin is smooth and unarmed. In the interior of 

 the bulbous anterior end there are a large number of granules of brown pigment. 



Somewhat similar forms have been described by Welch from the stomach of a 

 shark {Carcharias sp.) and by Kennie and Reid from the muscles of the Bonito. 



