364 
Ascarids in the British Museum 
creosote. In the older examples, from 28-38 mm. in length, it acquires 
a more distinct lumen, its walls at the same time becoming much more 
opaque and granular, and usually of a rather dark brown colour, so 
that the worm, when cleared in creosote, appears brown to the naked 
eye. 
In examples under 28 mm. in length, there is no indication (Fig. 3) 
of any caeca or diverticula springing from any portion of the alimentary 
canal 1 . 
In one specimen of about 28 mm. in length (PI. XIV, fig. 2), a caecum 
( C .) was beginning to spring from the anterior end of the chyle-intestine, 
in a forward direction, dorsally to the second portion of the oesophagus. 
In all examples of A. capsularia, from about this size upwards, such a 
caecum is present. It is short at first, but when the worm has reached 
a length of 38-40 mm. it has grown forward until it is nearly equal in 
length to the second division of the oesophagus (PL XIV, fig. 3, C.), 
round which it fits rather closely, having a concavity on its inner side. 
It has a moderately large lumen, and opens into the chyle-intestine 
just behind its junction with the oesophagus. 
In no case have I observed any backwardly-directed diverticulum, 
the dorsal intestinal caecum described being apparently the only 
appendage present, at least during the larval period. In examining 
creosote-cleared specimens one is apt to fall into the error of mistaking 
the posterior rounded end of the granular oesophageal organ, on the 
ventral side, for a diverticulum; but the careful study of a number of 
specimens shows that no caecum is really present in this position. 
There is a highly characteristic excretory gland on the ventral 
side of the anterior part of the body; this is present at all stages seen, 
and has the form of a single, flattened, ribbon-like cell extending 
throughout (roughly) the anterior third 2 of the body, and containing a 
very narrow lumen with frequent lateral branches. 
Anteriorly, from just behind the thickened posterior portion of the 
oesophagus, the giant excretory cell becomes much narrower, and its duct 
1 This is in entire disagreement with some of the published descriptions purporting 
to refer to A. capsularia; in some of these descriptions two diverticula are said to have 
been seen in examples only 10-20 mm. in length. I have seen some specimens of a form 
only 12 mm. long, from Gadus callarias, in which there were two well-developed caeca, 
but the second portion of the oesophagus, characteristic of the true A. capsularia, was 
wanting, and these specimens must certainly be regarded as belonging to a distinct species. 
In all probability it was this or some similar form which was seen by the authors of the 
descriptions referred to, and not the real A. capsularia. 
2 Not as much as six-tenths, as stated by Stewart. 
