MISCELLANEOUS. 265 
tion ; and the existence of the parasite is apparently dependent on the 
existence of the life of the other. If the one dies, so shall the parasite 
be destroyed. 
The subject of this paragraph infests the gills of the ling, to which 
it adheres with considerable tenacity. 
It is of a thin and flattened form, extending nine lines in extreme 
length, by about two in the broadest part. One extremity dilates into two 
portions, to the right and left, each composed of four tentacular-looking 
organs, a line in length. The remainder of the body tapers downwards, 
much like that of the common Planariz. A longitudinal internal cavity 
seems to consist of a larger and a smaller compartment ; besides which, 
numerous pinnate organs also occupy the substance of the body. The 
colour of the whole is bluish-grey. 
The body being remarkably thin, soft, and flexible, it applies closely 
to its site, with some adhesion ; and the two anterior portions clasp the 
rib of the gills in their fold. 
They have little other motion than slightly extending and con- 
tracting. 
Probably the tentacula are hollow. 
The site of the mouth could not be discovered ; but a ventral pore 
was visible after death. Can this be the orifice of a proboscis ? 
In a short time these animals lose the anterior portion by decay. 
On one occasion, twenty-nine specimens, of various dimensions, were 
removed from a portion of the gills of a ling ; and several were found on 
other occasions. 
It is doubtful whether their survivance is not very short, on 
removal. 
Pirate XXXVI. 
Fic. 1. Octodactylus inherens. 
2. The same, enlarged. 
