194 
Cystidicola farionis 
chitinous wall measuring 1 mm. x - 01 mm. The oesophagus is exceed¬ 
ingly long and narrow ; it measures about 2'7 mm. x ‘5 mm.; the anterior 
fifth is narrower than the succeeding portion and does not contain muscular 
fibres. The nerve ring encircles this slender part at its middle, i.e. about 
•3 mm. from the anterior end of the body. The male genital system pre¬ 
sents the following features : the testicular tube extends forwards without 
a single convolution from the cloaca along the ventral surface of the 
chyle intestine to end blindly at the junction of the anterior and 
posterior halves of the body. There are two spicules, unequal in size 
and thickness; the long slender spicule measures ‘75 mm., the short one 
16 x - 025 mm. The cloaca opens - 2 mm. from the tip of the tail and is 
enclosed on either side by a narrow cuticular ala extending from the end 
of the body along each lateral edge to a similar distance in front of the 
cloacal orifice. Within the alae are seen a double series of nipple¬ 
shaped papillae, there being nine pairs of prae-anal papillae and five 
single post-anal papillae in each ala. The components of the most 
anterior pair of prae-anals are considerably separated, whilst those of 
the other pairs lie close together, one slightly internal to the other. 
The female genital system opens by a very short vagina in the centre 
of the ventral surface, midway between the head and tail. 
From the vulva the vagina passes backwards, not forwards as stated 
by Schneider, for a distance equal to the diameter of the worm at that 
level and there divides into two uterine tubules, one of which continues 
directly backwards for a distance equal to a fourth of the body-length, 
doubling upon itself once in this distance in a coil of half that length 
and is then continued as an ovarian tubule. The other uterine tubule 
turns abruptly forwards from the vagina and describes a very similar 
course in the anterior region of the perivisceral cavity. Both ovarian 
tubules make two or three short coils. Those of the anterior tube only 
slightly overreach the junction of the oesophagus with the intestine, those 
of the posterior one do not extend so far 1 as to encroach upon the 
posterior sixth of the body. 
The mature female is ovoviparous, the eggs have thick shells with a 
curious tuft of exceedingly delicate filaments, two or three in number, 
attached to a small cuticular knob at either pole. The eggs measure 
- 05 x - 025 mm. and the shell is ‘005 mm. thick. The only other nema¬ 
tode in which such filaments have been noted, to my knowledge, is 
Ascarophis morrhuae, van Beneden (1870) 1 , in which species there are 
cuticular appendages at one pole only. 
1 van Beneden (1870), Les poissons des cotes de Belgique, Plate hi. fig. 11. 
