rOLYZOA OF WATJiUWOllKS. 437 



formation into the imago, or at least the eniei-genoe of the adult 

 form into the air, could not take place except by some chance 

 combination of circumsta.nces whicli would hardly occur very 

 often. It may be noted that Kraepelin, in commenting (p. 11) 

 on the absence of Chirojw mas -hirvse from the underground pipes 

 of the Hamburg system, points out that, according to his obser- 

 vations, these larvae are the most dangerous enemies of fi-eshwater 

 Polyzoa, whose delicate branches they tear to pieces. This might 

 have an important bearing on the distribution of the Polyzoa, 

 since, even in the most active period of tlieir growth, branches 

 containing statoblasts would be liberated by the Chiroiwmus- 

 larvse, and some of them would come to rest in places where a 

 new growth of the Polyzoa would, be started. 



In at least one of the samples, considerable numbers of a small 

 freshwater Oligochaste were found ; but I am not able to deter- 

 mine it from the preserved specimens in my possession. 



From the descriptions which have been given to me by 

 Mr. Chapman, there can be no doubt of the occurrence in the 

 Torquay system of small Gasteropods (perhaps Bithynia or 

 Limncea, and almost certainly Flanorbis), and of Asettus, Gani- 

 inarus, Cladocera, and Oopepoda. I have not had the opportunity 

 of examining specimens of any of these animals. 



I have no certain evidence of the occurrence of Iron-Bacteria, 

 but the appearances suggest that these occurred. In some places 

 the pipes were found to be coated with a thick black layer of 

 " peaty substance," cemented by iron-compounds. My colleague 

 Mr. A. Gepp, who has kindly examined one of the samples, tells 

 me that its condition is not such as to make the demonstration 

 of Iron-Bacteria ceitain, but from his experience of other similar 

 cases, he ha.s little doubt but that these had really been present. 



It may be remarked that the Torquay authorities have now 

 instituted a filtration-system ; and, judging from the experience 

 of other water companies, it may be presumed that the trouble 

 fi'om which they have suflered will soon be a thing of the past. 



(2) Lord Powis's Styche Estate (at Lydbury, North Shrop- 

 shire, near Market Drayton). 



In May 1912 I received information, through Dr. Augustus 

 Voelcker, of the Royal Agricultural Society, of the occurrence of 

 a Polyzoon which had been giving serious trouble near Market 

 Drayton. I later received specimens, in the fresh condition, 

 through the kindness of Mr. B. H. Newill, Lord Powis's agent. 

 The specimens in question were well-grown examples of Fluma- 

 tella fungosa, var. coralloides. In this case a feed-tank received 

 its water from a small open pool in which the Polyzoon was 

 proved to be growing. The water pa.ssed to the tank thi'ough a 

 strainer, which did no more than filter ofl:" the coarse detritus. 

 From the tank the water passed down an incline, in an under- 

 ground pipe, to a ram-chamljer situated about thirty-three vards 



30* 



