Page 186

186     lVisconsin Academy oj Sciences, Arts, and Letters.
task. The Polyp or Bryozoan cells seldom exceed a hundredth
of an inch, and in some species are less than a two hundred and
fiftieth of an inch in diameter. The cell walls and interspaces
are often dotted with pits or pores, the tdbuli of some authorities,
or studded with granules, whose dimensions are from one-half to.
one-tenth of the diameter of the cells. In the illustrated draw.
ings these surface maTkings are enlarged from twenty to fifty
diameters.
  The term corals, as applied to these forms, does not necessarily
imply that they belong to the radiate sub-kingdom. We find, in.
deed, that Professor Dana includes under this general term calc
reous or honey structures formed not only by Polyps and Hydroih
(Radiates), but by Bryozoans (Mollusca), and also by certa
low vegetable forms.
  In the classifications that have been made, the widest diversi
exists; no two authorities seem to agree, and the same species
relegated even to different sub-kingdoms by leading naturalisi
Of the thirteen genera recognized in this collection, Profess
Whitfield has placed Cloeters, ilontlculipora, Stellipora, Alvo
lites and Del~ayia under Corals; and Trematopora, FistuliPor
Palkcschaara, Stictopora, f'enestella, Retopora, Alecto and Au,
pora under Bryozoans.   S. A. Miller, of Cincinnati, classes ti
first group as Radiates of the Favosite group, Fisthlipora as
Millepore, J ulopora as an Alcyanoid coral, and the remaind
Bryozoans. Professor Dana differs from others in considering ti
Cllteles and related genera ilydroids instead of Polyp cora.
while Dr. Riominger, of Michigan, throws them out of the Radia
sub-kingdom altogether, and places the whole list under Bry
zoans. The close relationship and gradation of forms observe
in our specimens indicate that they should not be separated in
as widely differing divisions as has heretofore been done.
  Before considering this matter further, we will notice the re]
tionships that exist between some of these forms.  Beginnil
with those genera that are considered by all authorities as belon
ing to the Bryozoan order of Mollusks, we first notice the ti
representatives of the genus Stictopora, that are found in this ec
lection. (Fig. 1 represents S. elegantula, and Fig. 2 S. fragili!