24 
zooecia forming tlie basal expansion. In the elder parts of a co- 
lony there can be found several layers of such kenozooecia not only 
on the back-side but also on the front side (the inner side) of the 
colony. A colony of Retepora does not, as Hincks States, take its 
origin as a basal expansion, consisting of rudimentary zooecia, but 
(as I have found it in R. Beaniand) in the same manner as all other 
colonies of Bryozoa, namely as a single zooecium and the named 
basal expansion does not commence to develop, untill the colony 
has reached a certain size. Figure 18 in Hincks, British marine 
Polyzoa, pag. 394 which is a copy after Busk’s figure oi Lepralia 
lohata'^) is not as Hincks supposes the young state of di Retepora 
but on the contrary the relics of a pretty old colony, the greatest 
part of which has been broken of. 
Adeonidae. This family which I must maintain with the li- 
mitation given by Busk, is a very natural one. The very thick- 
walled zooecia, always lacking spines, are provided with numerous 
single-pored rosette-plates, in each wall arranged in a single row. 
No ooecia, but sometimes supposed gonozooecia. Although the zooe¬ 
cia as well as the avicularia are very strongly calcified, the avicu- 
laria always lack a cross-bar between the opercular and the sub- 
opercular area, and as already mentioned by Busk, the avicularian 
mandible always exhibits an articular process at each end of the 
base. While I am following Water s in referring the species pro¬ 
vided with a peristomial pore to the genus Adeonella, I shall re- 
tain the name Adeona for those species whose median pore enters 
into the zooecial cavity and which at present are referred to the 
very different genus Mkroporella. A third genus {Lohopora) must 
be instituted for such species as „Mieroporella'"'’ coscinopora Keuss. 
possessing a concave area perforated by a number of fimbriate pores, 
while „Schizoporella“ himunita Hincks must be regarded as a re¬ 
presentative of a fourth genus. 
Busk. The fossil Polyzoa of the Crag, PI. XXII, Pig. 4. 
