Polyzoa of Queen Charlotte Islands. 53 
by raised lines; surface thickly covered with roundish pune- 
tures, lustrous; orifice arched above, lower margin straight 
(without denticles), peristome raised, especially at the back 
and in front, where it rises in the centre into a blunt mucronate 
projection, which bends slightly inwards; the surface of the 
peristome smooth, entire, and very glossy. Avicularia 
none. Occium (?). 
Houston-Stewart Channel, not uncommon on shells. 
Mucronella prelonga,n. sp. (PI. IV. fig. 2.) 
Zoecia long and (usually) slender, quincuncially disposed, 
somewhat wider above than at the base (elongate-ovate, some- 
times appearing almost subtubular), convex, depressed below, 
rising towards the oral extremity; surface thickly covered 
with minute punctures, shining (the glistening appearance 
due to the presence of an epitheca) ; orifice suborbicular, peri- 
stome elevated round it, carried out in front into a very pro- 
minent process, often much thrown back and greatly elon- 
gated, sometimes simply pointed, sometimes bi- or trimucro- 
nate, on the inner side of it near the base a single, small, 
sharply-pointed denticle ; the upper margin produced in the 
centre into a tall spinous process, broad at the base, attenu- 
ated and membrano-calcareous above. Avicularia none. 
Oecium (?). Zoarium forming a whitish subcircular crust. 
Houston-Stewart Channel, on shell. 
A very picturesque form, distinguished by the remarkable 
processes on the upper and inferior margins of the peristome. 
The mucro in front is sometimes very greatly elongated, and, 
in such cases, the upper portion seems to be formed of very 
delicate membrano-calcareous material. ‘The spinous exten- 
sion of the peristome on the upper margin, which is much 
attenuated above, is also made up, to a great extent, of similar 
material. The subtubular character of the zocecia is a striking 
feature, though occasionally, and especially near the growing 
edge of the colony, they assume a more distinctly ovate form. 
Mucronella spinosissima, Hincks, form major. 
(Pl. IIL. fig. 3.) 
Zoecia broad-ovate, short, arranged in quincunx, very 
convex, sutures deep, surface smooth, subhyaline in the 
younger cells, opake in the older, a number of slender tubules 
immersed in the cell-wall immediately beneath the surface, 
and radiating from the margin towards the centre, the 
aperture opening out apparently on the surface, but closed ie 
a calcareous diaphragm ; the oral extremity of the cell muc 
