346 Prof. M‘Intosh on Cephalodiscus, a new Type 
attached to the wall of the chamber by the pedicle ; but many 
seem to have become detached and lie loose in the cavity. 
The products of these ova are yet unknown, though in all 
probability they are motive embryos which would carry to 
fresh sites the construction of the ccencecium. ‘Their compa- 
ratively large size recalls the condition in the Artisca, in 
which the great ova produce embryos about a third the size of 
the adult. 
Prof. G. O. Sars found in Rhabdopleura mirabilis (between 
the dorsal wall of the gullet and the anal region) a clear cellu- 
lar body, in which several nuclei were visible. He was of 
opinion that it could scarcely be a nervous ganglion, since it 
did not lie in the substance of the body itself, but only within 
the external skin. There would seem to be little doubt that 
this cellular body in Rhabdopleura is the homologue of the 
ovary in Cephalodiscus. 
The large ovigerous bodies over the eyes appear to be the 
homologues of the remarkable organ which occurs on the 
dorsal side of the cesophagus in the young Pedicellina (and 
which, according to Dr. Hatschek, is mesoblastic), and more 
especially of the double organ of the same kind described by 
Prof. Vogt and Dr. Barrois in the embryo of Loxosoma. 
The lamented Prof. Maitland Balfour was in doubt about Dr. 
Hatschek’s interpretation of the remarkable dorsal organ as a 
bud, since, “‘ owing to the deficiency of our observations on 
the attachment of the larva, this suggestion has not received 
direct confirmation; yet the relations of the dorsal organs in 
Pedicellina and Loxosoma respectively strongly confirm Hat- 
schek’s view of their nature” *. The very great develop- 
ment and unequivocal condition of the double organ in Cepha- 
lodiscus place the subject in a fair way for solution. ‘here 
cannot be much doubt as to their being ova in this form, 
while, again, the great distance from and independence of the 
actual buds on the distal end of the pedicle negative any close 
relationship between them. It is also worthy of note that in 
Cephalodiscus the eye-spots are so closely related to the surface 
of these organs that they are generally removed with them in 
dissection. It is further interesting that the buds in Lozo- 
soma arise from a region corresponding more or less to that 
containing the foregoing ova in Cephalodiscus, and not from the 
pedicle. The objection of Prof. Allman + to Oscar Schmidt’s 
view that the apparent buds in Lowxosoma are really detached 
from the ovary and developed on the body of the parent is 
clearly shown to be right, not only because the immature buds 
* Comparative Embryology, i. p. 246. 
+ Journ. Linn. Soc., Zool. xv. p. 2. 
