364 WILSON. [\'0L. IX. 



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 lar\'ae of silicious sponges at any 

 rate there is no constant point of attachment. 



VI. Remarks on the Gemmule Development of Sponges. 

 I . 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, i.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 



