364 WILSON. [VoL. UX. 
the gastrula mouth, but on the side. Fixation may also be 
delayed until the gastrula mouth has closed and spicules have 
begun to appear, in which case it is not stated by what part 
the larva attaches. In the solid larvae of silicious sponges the 
variation is much greater. Such larvae attach in some cases 
by the posterior pole, in others by the anterior pole, and yet 
in others on the side. All these variations may occur in larvae 
of the same species, for instance Maas records (16) that in 
Esperia he observed fifteen individuals attach by the posterior 
pole, seventy by the anterior pole, and five or six on the side. 
It thus appears that in the larvae of silicious sponges at any 
rate there is no constant point of attachment. 
VI. REMARKS ON THE GEMMULE DEVELOPMENT OF SPONGES. 
1. Asexual Development in General of the Sponges. 
The asexual method of development exhibits itself in sponges 
in a variety of ways. Besides the simple coelenterate-like 
process of budding which leads either to the production of 
new individuals or to the formation of more or less clearly 
marked colonies, and which is seen at its simplest in the 
calcareous sponges, the following instances of non-sexual 
reproduction may be called to the mind of the reader. 
In Oscarella, Schulze (27) found that hollow outgrowths 
were constricted off from the surface of the sponge, which led 
a free-swimming life for several days, ultimately sinking to the 
bottom and developing each into a new sponge. The out- 
growth contained a diverticulum from the canal system of the 
mother, and the wall of the outgrowth agreed in structure 
with the wall of the parent sponge, z.e. it contained flagellated 
chambers with the short afferent and efferent canals. The 
method of bud formation here employed seems to be funda- 
mentally the same as that exhibited in the calcareous sponges 
and the coelenterates. 
The propagation of sponges by cuttings may be mentioned 
in this connection. The experiments of Oscar Schmidt and 
those of the U. S. Fish Commission (made on the Florida 
j 
