1884. ] Zoölogy. 307 
This belt, when the larva is looked at from either extremity, 
is oval, and has its margin 
deeply indented with a notch 
(m) on one side. It divides 
the larva into two halves of 
unequal size, which may be 
called the anterior (a), and the «6... 
posterior (4). The anterior is 
hat-shaped and rounded at 
the apex. It is sometimes 
ceals the posterior half of the 
body, Fic. 1.—Larva from cain o ans a, ror 
The apex of the upper half Set beiisphares ciated betj, oncit 
of the body is rendered very apical projection; ž, posterior hemisphere ; 
prominent by reason of a tuft 4?) ciliated caudal prominences ; s, sete ; st, 
of cilia (cr). In one specimen apd lower extremity of larva. 
as y 0! arva. 
(Fig. 1) these cilia appeared to 
set on the edge of an orifice, which was widely open and 
every resemblance to a mouth. A small median pro- 
longation (0p) of a ridge on one side was noticed. In the 
walls of the larva near by was a pair of reddish pigment spots 
(oc). The union of the upper half of the embryo and the cili- 
ated belt is marked more especially on the ventral side by 
Opaque walls caused by pigment (ms) of a black color. The pos- 
~ terior body region is smaller and more pointed than the anterior, 
= and tapers uniformly from its fusion with a ciliated belt to two 
: a appendages (ff) at the lower pole, or posterior extremity 
, he larva. The posterior body region is unsegmented, and the 
_ Papilliform caudal appendages are covered with fine cilia. A vent 
Opens posteriorly between these two appendages, out of which 
: feces were observed to pass. On the side of the posterior half 
of body, opposite that in which the notch () in the margin 
the ciliated belt is found, several long spines (s) arise, which, 
in eee as long, resemble in general characters the spines 
itraria, They do not spring from a single or double? pro- 
terior ce as in Mitraria, but are appended to the side of the pos- 
tres part of the body which bears the ciliated papillæ. The 
t Prs uth was very difficult to discover, but in single specimens 
piesa hed seen in the region just below the ring of cilia in the 
ntation already spoken of in the margin of that structure. 
` This pigment calls to mind the “ Mesoderme oral,” in the figures of oung Poly- 
Coe tic (Recherches sur Api amera des Bryozoaires, Lille, Pre 
a sing figures of species of Mitraria by Müller. In Metschnikoff ’s species there is 
Prominence upon which the sete arise. 
