DEPARTMENT OF ZOOLOGY. 117 



o£ Structures exposed to Sea-action. An exhibit illustrative o£ this 

 subject has been arranged in one of the cases in the Central Hall ; 

 and a pamphlet, forming No. 10 of the " Economic Series," has 

 been published. 



VII. Platyhelminthes and Nemathelminthes. 



On numerous occasions parasitic worms inhabiting man or other 

 animals have been named for correspondents, and more particularly 

 at the request of the Imperial Bureau of Entomology, for corres- 

 pondents abroad. 



Enquiries on the subject of parasitic worms have also been 

 answered for the Queen's Hospital for Children, Hackney, and for 

 the Infant Welfare Centre, Soiithall, as well as enquiries from 

 private correspondents. 



VIII. Hydrozoa. 



On the question of the " Sea Moss " Fishery a correspondence 

 has passed between a member of the Trade and the Museum, with a 

 view to expanding the industry in home waters. 



IX. PORIFERA. 



Enquiries concerning the economics of Sponge-cultivation in the 

 West Indies (Bahamas, Turks Islands, and Virgin Isles) were made, 

 and samples of commercial sponges were named and reported on 

 from the point of view of their suitability for exploitation. 



VII. — Students and Visitors. 



The number of visits paid to the Zoological Department during 

 the year 1919 by Students and other persons requiring assistance or 

 information amounted to 7,459. This number includes the visits 

 paid by Students holding tickets entitling them to do special work 

 in the Exhibition Galleries. 



In the 10 previous years the numbers were as follows. From 

 1909 to 1912 inclusive the present Department of Entomology was 

 included in the Department of Zoology : — 



5,553 in the year 1918. 



6,314 





1917. 



7,018 





1916. 



8,020 





1915. 



9,235 





1914. 



9,982 





1913. 



12,564 





1912. 



12,175 





1911. 



12,443 



?9 



1910. 



11,461 



5? 



1909. 



Sidney F. Harmer. 



