30 Proceedings of the Roijal Society of Victoria. 



Lite History. — Sections across the colony show ova under- 

 going development in numbers considerably larger than the 

 parent animals. On the young hatching they swim away, but 

 with the foot bent so that their track is an irregularly curved 

 one. This distinctly favours their aggregation into groups. It 

 was very noticeable that all stages of growth from the young 

 female (Fig. 4) to the adult (Fig. 3) were to be seen in different 

 colonies, each colony being composed of individuals of the same 

 stage of growth and therefore age. With this fact in mind, and 

 observing the young females in swarms, I was led to watch their 

 movements. A swarm was isolated and watched. In the first 

 stage they formed a writhing mass adjacent to some solid particle 

 in the water, some individuals placing themselves in the position 

 they would assume in a fully formed colony (Fig. 21, a.), and 

 breaking away would wheel round and plunge into the mass 

 again. These manoeuvres were somewhat puzzling, but I 

 ultimately satisfied myself that at this stage the animals pour 

 out a transparent mucous and congregate in its midst, and the 

 position of animals as at (a.. Fig. 21) is due to being attached 

 to it by the foot, while the ciliary action of the corona tends to 

 draw them from it, and their leaving the colony is due to the 

 attachment giving way. In three hours the swarm had so 

 arranged itself that the individuals were more radially placed, 

 and about their now adjacent feet was a mass of granular 

 particles (Fig. 22, e.g.) connecting them with the particle of 

 vegetable matter (a.). Mounts made later clearly showed this 

 cement to issue from the terminal pore. Next day a distinct 

 peduncle was formed (Fig. 23). The colony was watched for 

 three days, and during this period the growth of the peduncle 

 went on. Being in a small quantity of water its movements 

 became less vigorous, and it was killed and mounted. Examina- 

 tion showed it to be of essentially the same structure as an adult 

 colony. The first deposition of mucous in Stage 1 (Fig. 21) would 

 appear to arise from the mucous glands (Fig. -4, m.g.), either exud- 

 ing from the surface or by way of the terminal pore, and the denser 

 cement laid down in Stage 2 (Fig. 22) from the special cement 

 glands (Fig. 4, s.c.g.), for these two glands are filled with granular 

 material which does not diminish until Stage 2 is reached, when 

 it soon becomes exhausted. The contents of these special cement 



