ON ARHYNCHUS HEMIGNATHI. 213 
however, seemed less mature than those lying in the head. 
Lying amongst the various organs in the body-cavity were 
a number of very finely granular masses, which I take to be 
the masses of spermatozoa (figs. vi and x). Of the complex 
system by means of which the ova leave the body, little could 
be made out beyond the fact that a well-marked funnel is 
present opening into the posterior end of the body-cavity 
of the trunk (fig. 1x). I failed, however, to find a second 
opening near the narrow end of the funnel such as occurs 
in other forms, but this may have been due to the poor state 
of preservation. 'The funnel leads into a duct which opens 
on the posterior end of the trunk. 
The testes are two in number, and lie one behind the other 
in the ligament, though owing to its looping both may appear 
in the same transverse section. The spermatozoa do not 
escape into the body of the male as the ova do into that of the 
female, but pass down a duct in the ligament which opens 
at the end of the body. Traces of accessory glands were seen, 
but the details were not clear. 
The brain lies on or in the ligament just behind its point 
of attachment to the skin of the head (figs. x1 and x11). 
Owing to the disruption of the ovaries in my female specimens 
the ligament could not be traced very far, but in the only 
male it reached from one end of the body to the other. ‘The 
brain consists of a few large ganglion cells with a clear homo- 
geneous cytoplasm and deeply-stained nuclei; the divisions 
between the cells were very sharp and straight (fig. xr). In 
the females this mass of cells lay in the ligament; in the male, 
on the other hand, it occupied the centre of the fibrous and 
muscular strands which compose that body (fig. xv). In the 
former I could trace no nerves leaving the brain, but in the 
male two nerves surrounded by muscles pass backward ; these 
obviously correspond with the retinacula of other forms, 
Classification. 
Until recently the group Acanthocephala included but one 
genus, Echinorhynchus, which comprised several hundred 
