237 
object in writing to put on record the results of my own in- 
dependent observations, which, so far as they go, are entirely 
in agreement with those obtained by Smitt. 
I have studied the history of the “ germ-capsule” more or 
less in many species, but more especially and most thoroughly 
in Bicellaria ciliata (Linn.). In general structure it is a 
granular mass, of somewhat variable form, enveloped in a 
membrane, which is thickly covered with pigment spots. 
It is found attached to the cord that connected the polypide 
with the base of its cell, occupying, indeed, much the same 
position as it did when an integral portion of the digestive 
sac. The first sign of its having entered upon a course of 
development is the appearance of a clear space, and then of 
a small swelling or protuberance on its upper surface. This 
bud is of a light greyish colour, and shows distinctly in 
contrast with the dark reddish-brown of the capsule itself. 
It increases in size, and is gradually moulded into a tentacu- 
lar crown and rudimentary intestinal canal, and at last a 
perfect polypide replaces the original tenant of the cell. The 
budding tentacles are of a light colour, while the lower 
portion of the “ groddkapsel”’ retains its dark-reddish tint, 
so that the course of development is easily followed. It 
seems to correspond very closely with that which has been 
described by Nitsche in his account of the development of 
the primary cell from the larva in Bugula flabellata... Ihave 
sketches of various stages of growth, made at the moment of 
observation, which would have accompanied this paper had 
there been time for the preparation of the engravings. 
I may remark, further, that Nitsche’s opinion, that the 
so-called “ germ-capsules,” or “‘ brown bodies,” in the cells 
of the Polyzoa, are “‘mere remains of decaying polypides,” 
is quite inconsistent with the history of their forma- 
tion, which has not received sufficient attention. The 
“ oyoddkapsel” is in no true sense “the remains of a 
decaying polypide.” It is a special body, elaborated out of 
the substance of the polypide, passing through a fixed and 
constant course of development, which commences at a com- 
paratively early period in the life of the polypide, and exhibit- 
ing at last a definite form and structure. Pa 
I have repeatedly studied its origin and formation in 
various species, and always with the same result. At a 
certain point in the life of the polypide a very marked change 
is seen to be taking place towards the base of the body. It 
consists in the gradual separation of the lowest portion of 
| Vide his admirable paper, “ Zur Kenntniss der Bryozoen,” 1869. 
