22 



varied fauna in the pipes of certain foreign waterworks, notably 

 at Hamburg and Rotterdam. As was first shown by Kraepelin, 

 the Polyzoa play a prominent part in the activity of the pipe- 

 fauna, by feeding on Diatoms and other microscopic organisms, 

 and serving in their turn as the food of other animals which prey 

 on one another. The nutritive matter rendered available by the 

 presence of enormous numbers of Polyzoa is thus in large measure 

 responsible for the existence of other constituents of the fauna, 

 which may include even fishes, such as the Eel and the Stickle- 

 back. The organic material supplied by the disintegration of the 

 Polyzoa and other animals is believed to be important for the 

 nutrition of Iron-Bacteria, which are well known to cause the 

 most serious trouble in waterworks. 



He then gave some account of five cases, which had recently 

 come under his own observation, of the occurrence of Polyzoa in 

 English waterworks in sufiicient numbers to give rise to very 

 serious inconvenience. In one or two of these cases the advice 

 given by Kraepelin, in his paper on the Hamburg pipe-fauna, was 

 being followed, by the introdvxction of a system of filtration, the 

 principal object of which is to remove the microscopic organisms 

 on which the Polyzoa, and ultimately the whole assemblage of 

 animals in the pipes, depend for their nutriment. 



The Polyzoa found in the five systems considered were referred 

 to four species, and some account was given of the synonymy and 

 distinguishing features of these. One of the species found was 

 Paludicella articulata Ehrb., and the specimens v/ere remarkable 

 for the profusion with which hibernacula or winter-buds were 

 being produced. The examination of the hibernacula resulted in 

 the discovery of some evidence with regard to the mode of 

 development of these structures — a subject on which no observa- 

 tions appear to have been hitherto published. The evidence 

 recorded may have some bearing on the question whether there 

 is any homology between the hibernacula of Paludicella and the 

 statoblasts of Phylactoleemata. 



A paper, communicated by Mr. Cyril Crossland, was received 

 from Mr. A. W. Waters, F.L.S., F.G.S., entitled " The Marine 

 Fauna of British East Africa and Zanzibar, from Collections 

 made by Cyril Crossland, M.A., B.Sc, F.Z.S., in the Years 

 1901-1902. Bryozoa— Cheilostomata." 



In the collection dealt with from the neighbourhood of Zanzi- 

 bar thei^e are 76 species or varieties of Cheilostomatous Bi-yozoa, 

 almost all being fi-om 10 fathoms or under, so that for a shallow- 

 water collection it is a very large one. 



The nature of the articulation is traced in the Scrupocellaridse 

 from the simplest to the more differentiated forms, and Cateni- 

 cellidse with long nodes with many ovicells are described. The 

 ovicells at the end of erect Aetea are again described. The author 



