180 REPORT— 1883. 
fore be ont of the pale of competent authority in thus seeking to extend 
the principle to Fossil Polyzoa. Before closing these remarks, however, 
I cannot help saying that to seek from the embryologist information that 
would help to dispel the cloud of doubt that surrounds the earlier history 
of the Paleozoic Polyzoa seems to be somewhat fanciful. Yet, in the 
latest researches of Dr. Jules Barrois on the Embryogeny of Cyclosto- 
matous Polyzoa,! we are furnished with most important conclusions 
respecting the ancient group, as a result of researches on living forms. 
Barrois says: ‘To conclude, we may put forward the hypothesis of the 
very ancient existence of a group of Probryozoa, composed of swimming 
organisms, free, and possibly analogous to the Rotifera (at least as regards 
the aspect and general arrangement of the body), and of which the few 
larvee of Hntoprocta that we have nowadays represent the sole survivors ; 
from this group the existing Bryozoa are derived by adaptation to a new 
mode of life; certain larvee have accustomed themselves to creep. . . 
upon their oral surface instead’ of swimming freely through the water ; 
and hence the changes . . . which produce the Bryozoan form.’ 
A very cursory examination of the Synopsis of Primary Division of 
the Polyzoa,” formulated by Mr. Busk, will show that to a large extent 
these are founded upon recent types. The orders include both fresh- 
water and marine species, and being originally devised by Dr. Allman for 
his classification of the Freshwater Polyzoa, the order Gymnolemata was 
necessarily extended for the inclusion of the whole of the Marine Polyzoa 
as well. The three suborders of Mr. Busk—Cheilostomata, Cyclostomata, 
and Ctenostomata—are founded upon certain peculiarities of the mouth of 
the cell. In the first of these divisions the orifice, or mouth of the cell, 
is subterminal and of less diameter than the area of the cell. In the 
second the cell is tubular, and the orifice or mouth is terminal ; but as the 
third suborder has characters unknown to me in a fossil state, it may be 
conveniently dispensed with in this Report. The two divisions already 
alluded to are made to include the whole of the Fossil Polyzoa of the 
Crag, and also the whole of our Marine Polyzoa, British or foreign. At 
present I have no knowledge of any genus or species found within the 
European area at least, in either the Cainozoic or Mesozoic, that may not 
be included in the suborders of Mr. Busk, if slightly modified to meet a 
few rare cases. When, however, we get beyond the Mesozoic epoch, and 
pass into the Paleozoic, the cases are very different. It is here that we 
meet with types evidently belonging to the class Polyzoa, in which the 
cell is devoid of either terminal or subterminal stomata. In making a 
superficial examination of these we find that the true or normal cell is 
deeply set in the branch, stem, or frond, and what we see of the superficial 
orifice is not the mouth of the cell, but what may be fittingly called the 
vestibnle ; the true orifice is concealed. In many of the Paleozoic types 
the vestibule is very large, and generally filled with matrix. The genera 
in which the concealed stomata may be casually observed—for sections 
are required to show the distinct features—are species of Ptilodictya, Arca- 
nopora, and Rhabdomeson. Besides the mere stomata there are certain 
peculiarities of the grouping of the cells, and of the interspaces between 
cell and cell, that would afford good diagnostic characters ; but of them- 
selves they are not of sufficient importance for my purpose. It is very 
1 Ann. Mag. Nat. Hist. Nov. 1882, p. 402. 2 Crag Polyzoa, p. 9. 
