TWO NEW SPECIES OP THE PHOKONIDEA. 
265 
tliat it may easily be passed over. I do not think^ however^ 
that it is entirely eliminated as in Pli. capensis described 
by Gilchrist (7), who suggests that such a character of the 
septum would probably be of value in specific determinatioip 
stating that Ph. hippocrepia agrees with Ph. australis 
in having tlie septum uniformly invaded by a basement 
tissue. In Ph. vancouverensis there is certainly no 
uniform median layer, so I have included this characteristic 
ill the table at the end as a minor feature distinguishing this 
specimen from Ph. hippocrepia. 
The mesenteries also contain a veiy thin layer of basement 
tissue. 
Nervon.^ System. — The ring of nervous tissue at the 
base of the lophophore is quite apparent (Fig. 5, n. r.) and is 
continued posteriorly, following the course of the tentacles, 
up each of which passes a fine strand of the same tissue. 
Across the dorsal surface in front of the anus is a large 
ganglionic mass (Fig. 5, g.) composed of the usual punctated 
tissue with definite striation and numerous cells with lai'ge 
nuclei. This tissue is everywhere in close relation with the 
inner ends of the elongated epithelial cells. 
In some sections can be seen a small lateral nerve-cord 
lunning along each side of the body close to the point of 
attachment of the lateral mesenteries (Fig’. 2, I. n.), and {)io- 
jecting into the basement tissue as a small mass of punctated 
tissue. These appear to be very short, for they have not 
been seen beyond the oesophageal region. 
Traces of nervous tissue have been observed in the centre 
of the pit at the proximal end of the body and also along the 
alimentary canal on the outer side of the epithelium. This is 
especially markeil in the upper oesophageal region opposite 
the nerve-ring. Gilchri.st (7) mentimis this sensoiy jiatch and 
suggests that it may represent an organ of taste. 
Alimentary Canal. — The various regions of the alimen- 
tary canal are named in the figures in accordance with Cories 
views (3), these being also adopted by Selys Longchamps 
(14). 
