INTRODUCTION. 



xiii 



large collection of examples of Fishes sent home by- 

 officers of the Medical Staff, and which still remain 

 unopened, in the Fort Pitt Museum at Chatham ; but 

 I am not without hope that these may shortly undergo 

 comparison with the drawings which exist of each, and 

 that this branch of the island fauna may at last attract 

 the attention to which its richness so eminently en- 

 titles it. 



In the department of Entomology much has already 

 been achieved ; but an extended area still invites future 

 explorers ; and one which the Notes of Mr. Walker 

 prefixed to the List of Insects in this volume, show to 

 be of extraordinary interest, from the unexpected con- 

 vergence in Ceylon of characteristics heretofore sup- 

 posed to have been kept distinct by the broad lines 

 of geographical distribution. 



Eelative to the inferior classes of Invertebrata very 

 little has as yet been ascertained. The Mollusca, espe- 

 cially the lacustrine and fluviatile, have been most 

 imperfectly investigated; and of the land-shells, a 

 large proportion have yet to be submitted to scientific 

 examination. 



The same may be said of the Arachnida and Crus- 

 tacea. The jungle is frequented by spiders, phalangia l , 

 and acarids, of which nothing is known with certainty ; 

 and the sea-shore and sands have been equally over- 

 looked, so far as concerns the infinite variety of lobsters, 

 crayfish, crabs, and all their minor congeners. The 



1 Commonly called " harvest-men." 



