No. 9. — -1856-8.] CEYLON NUDIBRANCHIATA, &C. 



77 



Las enabled me to prosecute researches in more than one unex- 

 plored field of Natural History. I had for my guide the example 

 of those great and good men, who deign to look upon even my 

 labours as worthy of encouragement, and who do not consider 

 the pursuit of the Naturalist as incompatible with the duties of 

 a Military Surgeon. Dr. Johnson, himself a successful Medical 

 practitioner and zealous Naturalist, (in his celebrated work on 

 British Zoophytes,) observes, in his remarks on Doctors who are 

 also Naturalists, that " that very activity of mind and perspica- 

 city which originated and upheld their sagacity and success as 

 practitioners, were sure to carry them far in whatever side-path 

 the natural bent of their taste led them, for the occupation and 

 entertainment of the leisure hours which the busiest must have, 

 or may create. Idleness has no leisure. * * * There never 

 was a time when it was necessary to vindicate, to any but the 

 io-norant, the erratic excursions of medical men into the fields 

 of science and literature ; for assuredly the rank which the 

 profession, as a body, has taken and holds in public estimation, 

 depends for its patent, in part at least, on the scientific and 

 literary character of its professors ; and by continuing to 

 support that character they will best secure it from the vul- 

 garity of a common mercature, or the selfishness of a venal 

 quackery." 



My earliest researches, since my return to Ceylon, were 

 directed (with the aid of the microscope) to those minute forms 

 of animal and vegetable life called animalculae, and Diotomacece. 

 I have already communicated to another channel the observa- 

 tions I have made among these interesting microscopical crea- 

 tures, found in fresh and sea water. In this paper, I propose to 

 communicate to the Ceylon Branch of the Koyal Asiatic Society, 

 my researches among some of the least known, but most 

 interesting, species of marine animals. 



Finding that scarcely anything is known of the many naked 

 Molluscs of this part of the Indian Ocean, I have availed myself 

 of the present favorable opportunity offered by the Ceylon 

 Government, for the investigation of the Natural History of the 

 Pearl Oysters, to extend my researches also to a numerous family 



