BHITISTI MUSEUM (NATURAL HISTORY). 99 



A set of sheets of the Catalogue (as far as printed off), 

 stamped with index-letters showing in which Department 

 the various works are to be found, has been supplied to each 

 Department. 



The number of viaits paid to the Library by Students and 

 others during the year (irrespective of the staff" and persons 

 to whom the use of a key is granted) was 1,245. 



Index Museum. 



The exhibits in the Entrance Hall, collectively known as the 

 Index Museum, have been enriched during the past year by a 

 donation from Dr. G. Abbott in the form of an extensive 

 series of limestone concretions bearing a spurious resemblance 

 to organic remains. The classification, labelling and arrange- 

 ment of these specimens were eff'ected under the immediate 

 supervision of the donor. 



To the series of models of the gills of Lamellibranchia 

 mentioned in the last report, two new models have been 

 added, rendering the series a complete concrete exposition 

 of the modern views on the evolution of the gills of these 

 Molluscs. 



In the centre of the Hall have been placed preparations 

 showing the structural diff'erences between the malaria- 

 carrying Mosquito or Gnat (Anopheles) and the common 

 Gnat (Culex), and the complete life-cycle of the parasite of 

 malaria in its two phases, asexual, in human blood, and 

 sexual, in the body of the Mosquito Anopheles, For com- 

 parison with the Anopheles and Culex a large drawing and 

 an actual specimen of the harmless Midge or Black Gnat 

 {Ghironomus) are included in the series. 



The specimens illustrating the principle of Protective 

 Mimicry and Cryptic Coloration, formerly exhibited in a case 

 in the centre of the Hall, have been transferred to one of the 

 side recesses. By the addition of new specimens the series 

 has more than doubled in bulk. The instances are now 

 classified according to modern views on the subject, and a 

 further improvement lies in the fact that in the case of 

 mimetic Lepidoptera both sexes are exhibited, so that it may 

 be seen at a glance whether the mimicry is common to the 

 male and female or is confined to one sex. 



Numerous experiments have been conducted with a view 

 to ascertaining the best mode of displaying Fishes in museums, 

 and in the part of the Hall devoted to recent acquisitions 

 the more successful results, in the way of alcohol-mounted 

 specimens, coloured casts, coloured models, stuff'ed skins, fee, 

 are exhibited. 



130. H 



