12 
THE VOYAGE OE H.M.S. CHALLENGER. 
surface of the body- wall. It is coloured black by pigment balls, 0‘002 mm. in size. The 
cavity also contains a colourless, partly granular, partly hyaline, protoplasmic mass. 
No reproductive organs were developed. 
The internal wall of the musculature bears a simple layer of non-nucleated cells. 
The slightest injury to the animal causes the epidermis to roll up, and the same 
happens to a less extent with the cuticular fibres, and still less with the muscles. This 
is not to be wondered at when we remember the enormous pressure to which the animal 
is subjected at a depth of 11,000 to 12,000 feet. All elastic membranes and fibres roll up 
when suddenly relieved from a great pressure or strain to which they have been sub- 
jected. The very firm and hard cuticle can obviously bear a great pressure. The species 
appears to spend its entire life free, for the head end exhibits no boring apparatus by 
which the worm might penetrate the organs of other animals. The specimens are all 
without reproductive organs, and may be described as larval. They are the largest free- 
living Nematode larvae as yet known, and the adult form must be one of the largest free- 
living Nematodes. 
It is unfortunate that no sexually mature specimens were found, as they could not 
but have exhibited peculiarities, probably more marked than those which make even the 
larvae interesting. 
The most closely related genera are Gordius and Mermis, which are, however, 
destitute of an anus, and parasitic in their larval life. The musculature of the above- 
described genus is markedly peculiar, and quite different from that observed in other 
Nematodes. 
B. CESTODA. 
11. Taenia clavulus , n. sp. (PL II. figs. 11, 12). 
Specimen labelled : “ Taenia from intestine of Ptilorhis alberti, Cape York.” 
The vessel contains numerous fragments of Taeniae, which probably belong to two 
specimens, and also the anterior portion of a proglottis chain with the attached scolex. 
The latter is oval, 0‘84 mm. long by 0‘6 mm. broad, the suckers are elongated (0'3 mm.), 
situated on the anterior third of the scolex, and exhibit firm, prominent, almost con- 
tiguous margins. The apical surface of the scolex bears a smaller fifth sucker, 0'084 mm. 
in diameter, armed with a double row of nail-sbaped rods. These have not the usual 
form of Taenia hooks, are very small (only O'Oll mm.), and number about sixty. The 
first proglottides measure 0’29 mm. in breadth and 0’048 mm. in length ; the last are 
IT mm. broad and 072 mm. long. The segmentation begins about 0'9 mm. behind the 
scolex. 
Helminths have not been previously observed in Ptilorhis alberti, Elliot. 1 
1 Report on the Birds, Zool. Chall. Exp., part viii. p. 87. 
