116 ACCOUNTS, ETC., OF THE BKITISH MUSEUM. 



formed by the British Science Guild to consider scientific research 

 in relation to fisheries. At the request o£ the R.A.M.C. officer in 

 charge of Anti-Malaria work at Sheppey, Mr. Regan went to 

 Sheppey on March 5th to inspect the marshes and advise with regard 

 to fishes that eat mosquito larvae. 



In connexion with enquiries from the Colonial Office as to 

 poisonous Fishes in the West Indies, arrangements have been made 

 for Mr. P. Lechmere Guppy to collect for the Museum, in order 

 that fishes reputed poisonous may be accurately determined. 



IV. MOLLUSCA. 



Advice has been given on the following subjects : — Choking of 

 water-mains carrying sea-water, by mussels in a large power-station 

 at Portobello, N.B. 



Means of determining Mollusca that are recognised as inter- 

 mediate hosts of Bilharzia (many enquiries). Determination of 

 Mollusca suspected of transmitting Fasciola liepatica (Liver Fluke) 

 in North Rhodesia and of Bilharzia on the Gold Coast. 



Determination of Mollusca habitually eaten by Australian and 

 New Zealand food-fishes. 



Following on an enquiry from the Chief Engineer of the 

 Metropolitan Water Board, investigations were made on the subject 

 of the " Dreissensia " nuisance in waterworks, on remedial measures, 

 and on means of prevention. The fresh water mollusc Dreissensia 

 polymorpha frequently gives rise to serious trouble in waterworks by 

 causing obstruction in the supply-system, and by pollution due to 

 death and decay of the animals. The area of distribution of this 

 prolific mollusc has been extending during the last fifty years, and 

 the trouble arising from its presence in waterworks may tend to 

 increase rather than diminish unless due precautions are taken. 



V. Arachnida. 



1. Mites from domestic animals, especially poultry, determined 

 for the United States Bureau of Agriculture. 



2. A mite (^Actineda vitis) feeding on aphides, especially woolly 

 aphis, determined. 



3. An alleged poisonous spider (Latlirodedus mactans, var.) 

 named for the Wellcome Bureau of Scientific Research. 



4. A species of " Red Spider " (^Paratetranyclius simplex) 

 damaging date-palms in Mesopotamia, described. 



5. " Red Spiders " injurious to peaches, vines, etc., named for 

 a correspondent. 



6. A species of mite of the genus Tarsonemus, supposed to 

 damage ferns, determined. 



VI. Crustacea. 



The Assistant in charge of Crustacea has been largely occupied 

 with the study of Marine Boring Animals (including Mollusca and 

 Worms as well as Crustacea) submitted for examination by the 

 Committee of the Institution of Civil Engineers on the Deterioration 



