Polyzoa of Queen Charlotte Islands. 55 
the centre of the zocecium. They vary much in length, some 
being almost rudimentary, and others extending nearly or 
quite to the centre of the cell. Not unfrequently short tubes 
alternate with the longer ones; and commonly the latter seem 
to be composed of several short tubules, which originate one 
from the other, a little below and behind the orifice. In the 
younger zocecia the tubules are, I believe, on the surface; but 
they are soon overgrown by the calcareous crust, and in older 
states they are completely concealed by it. In highly calci- 
fied colonies this feature disappears, and the cells present a 
uniform opake surface. The tubules traverse the neck-like 
portion of the cell, and the numerous oral spines seem to be 
nothing more or less than their free extremities projecting be- 
yond the margin of the peristome. 
It is difficult to form a conjecture as to the precise import 
of the tubular system, and the more so as there has been no 
opportunity thus far of tracing the growth of the cell-wall and 
the mode in which the tubules originate. 
The primary cell of Mucronella spinosissima closely resembles 
that of M. Peachit. 
RetTepora, Imperato. 
Rtetepora Wallichiana, Hincks. 
Houston-Stewart Channel, 15-20 fms. 
[Spitzbergen, 20-80 fms., Finmark, Godhaab, 150 fms. ] 
This form was first described by Smitt * as a variety of R. 
notopachys, Busk, a Crag fossil. Some years later the exa- 
mination of specimens obtained by Dr. Wallich in Davis 
Straits convinced me that it was a distinct species, and it was 
accordingly described as such (‘ Annals’ for Jan. 1877, 
p. 107), with the name which Mr. Busk had already assigned 
to it in MS. 
R. Wallichiana, when fully developed, forms intricate 
convoluted and chambered masses of considerable size. It is 
one of the many arctic species which have migrated to the 
Queen Charlotte Islands. 
Family Celleporide. 
CELLEPORA (part.), Fabricius. 
Cellepora incrassata, Lamarck. 
Houston-Stewart Channel; Virago Sound, incrusting the 
stems of Hydrozoa. 
* “Kritisk forteckn, Ofver Skandinavien’s Hafs-Bryozoer,” Q#fvers. 
Kongl. Vetensk. Akad, Forhandl. 1867, Bihang. 
