18 CEYLON PEARL OYSTER REPORT. 



Mr. Hornell and I arrived iu Ceylon on January 20th, 1902, so as to leave some 

 weeks free before the end of February, when we proposed to join Captain Donnan in 

 his annual inspection of the pearl banks. This interval I had thought essential in 

 order that we might perfect and test our apparatus, find out the necessary methods of 

 investigation, and make ourselves acquainted with the biological conditions in the 

 Gulf of Manaar, and with any special features in which that region differs from the 

 other seas around Ceylon. For the purpose of this preliminary biological survey 

 the Government of Ceylon placed the s.s. " Lady Havelock"* at my disposal, in the 

 first instance for a period not to exceed three weeks. This first cruise lasted for 

 twenty days (January 30th to February 19th), and was followed, for reasons given 

 below, by a second cruise of about four weeks in the same vessel. After that we 

 joined Captain Donnan on his inspection barque. 



In the first cruise of the " Ladv Havelock " my objects were : 



(1.) To investigate the general biology of the seas around Ceylon, and especially 



of those places where pearl oysters were said to exist. 

 (2.) To examine more carefully any localities that seemed to be likely spots for 



uncharted pearl oyster banks. 

 (3.) To investigate the fauna, the bottom deposits, and the characters of the 



water in the Gulf of Manaar for comparison with the conditions at 



Trincomalee, Galle, and other parts of the coast. 

 (4.) To make experimental hauls of the fish- and the shrimp-trawls round the 



coast, so as to obtain information as to the prospects of fish-trawling as 



an industry in Ceylon waters. 

 (5.) To look into any other departments of marine biology which might be 



prosecuted as useful industries. 



We joined the s.s. " Lady Havelock" on the evening of Thursday, January 30th, 

 1902 ; and started from Colombo harbour early the following morning. The course 

 during this cruise is shown by the strong dotted line on the map (p. 19), and the 

 observing stations are marked by a cross within a circle (see also more detailed map 

 on p. 82). After steaming northwards for some hours the dredge was put overboard 

 for the first haul about 11 a.m., at 5 miles S.W. of Negombo in 12^ fathoms of water. 

 The rest of the day was occupied in dredging and trawling along an area about 5 miles 

 in length extending opposite Negombo Lake from Pamunogan at the south to 

 Negombo, keeping from 4| to 5^ miles off shore, in from 12 to 20 fathoms. A little 

 further out the sea deepens very rapidly, 50 fathoms being reached 10 miles from 

 land, 70 fathoms a mile further out, over 700 fathoms at about 18 miles west of 

 Colombo and 1000 fathoms at about 20 miles from land. My object in working along 



* I ought to state that on the whole the " Lady Havelock " proved a very suitable vessel for the 

 purpose, and I desire to record also my sincere thanks to Captain Campbell and the officers and others 

 on board for the pains they took to carry out my wishes. The steamer is shown on p. 54. 



