94 BULLETIN OF THE 
The Bugula larve, on the contrary, I have never found in the tow, but 
they swarm out from stocks gathered in the morning and placed in a 
glass vessel; and I can confirm Nitsche’s (69, p. 9) observation that they 
settle and begin their metamorphosis within “a few hours” after hatch- 
ing. One rarely or never finds these larve succumbing to the unfavor- 
able conditions of the aquarium before metamorphosing. From these 
observations I conclude that the Bugula larva has a very much shorter 
life than Cyphonautes. Now, since the larva, owing to its shortened life, 
has no need of functional entoderm, and since entoderm can be of use to 
the larva only, no part of it going over into the tissues of the primary 
polypide of the stock (except as food material), functional entoderm is 
not developed. In other genera, its rudiments have become less and 
less important in the ontogeny, and, finally, in Phylactoleamata are 
wholly lost. 
That the entoderm should reach its last stage of degeneration in 
Phylactolemata is easily understood when we consider that the larval 
period is passed in a closed oœcium, from the wall or neck of which it 
receives nourishment as a parasite docs. Moreover, by the delay in the 
period of hatching, as well as by precocious development of polypides, one 
at least of the latter is usually functional in the just hatched stock, for 
there is sometimes found at least one polypide in the newly hatched 
larva, which is partly extruded, and therefore capable of feeding, and 
thus of supplying the whole stock with nutriment. Of what advantage 
to a species could be the development of a functional larval entoderm, 
which should go to form no part of its adult tissue, provided the larva 
was contained in a uterus during its early stages, and was provided with 
the adult digestive organs in a functional condition before leaving the 
uterus 4 
Those who maintain that the inner layer is to be regarded as entoderm, 
and are still unwilling to place the Bryozoa among the Colenterata, must 
account for the absence of mesoderm. Korotneff (’89, p. 400) finds de- 
generating cells in the blastocosl before this is wholly obliterated by the 
extension of the inner layer. These he seems to regard as degenerate 
mesoderm. According to his view, then, the entoderm gives rise to 
the muscularis, — for this arises from the inner larval layer, according 
author does not there state whether stomodw#um and proctodæum are formed on 
the blastoporie side of the larva. He accounts for the existence of an alimentary 
tract in Cyphonautes by the fact that it undergoes its development disconnected 
with the parent, while almost all other Bryozoa pass their early stages in the 
parent or some protecting zoöid (ocecium, ovisac, ovicell). 
