PREFACE. 
This Guide deals with the specimens which are exhibited in the 
Southern half of the “ Insect Gallery.” The great group 
Arthropoda, or animals with jointed legs and (usually) a hard 
exoskeleton, are here considered, with the exception of the Insects, 
which are described in a separate Guide. The present work is 
thus concerned with the Crustacea, mainly aquatic in habit, and 
represented by familiar animals such as Shrimps, Lobsters and 
Grabs ; with the Arachnida, the Scorpions, Spiders, Ticks and 
their allies ; with the Onychophora, constituted by the singular 
animal known as Peripatus ; and with the so-called Myriopoda, 
including the Millipedes and Centipedes. 
The section on the Crustacea is written by Dr. W. T. Caiman, 
that on the Arachnida and Myriopoda by Mr. A. S. Hirst, and the 
portions dealing respectively with the Onychophora and with the 
Pentastomida (the latter regarded as degenerate Arachnida) by 
Mr. F. Jeffrey Bell. 
Mr. R. I. Pocock, who was formerly in charge of the Arachnida 
and Myriopoda, and whose responsibility then included the arrange- 
ment of many of the specimens now exhibited, has been kind 
enough to read the proof-sheets dealing with those groups. 
The thanks of the Museum are due to Messrs. A. and C. Black 
for their permission to use certain blocks from Part vii (Dr. Caiman’s 
volume on Crustacea) of the “ Treatise on Zoology,” edited by 
Sir Ray Lankester, k.c.b., f.r.s., who has also given his sanction 
to their use in this Guide-Book. Figs. 10, 11, 13, 15, 18-22, 26, 
27, 30 are derived from this source. 
SIDNEY F. HARMER, 
Keeper of Zoology. 
British Museum (Natural History), 
Cromwell Road, London, S.W. 
February , 1910. 
