The result of our examination of the pearl banks, on this occasion, was such as to discourage the hope of an early fishery. The oysters in point of number were abundant, but in size they were little more than "spat," the largest being barely a fourth of an inch in diameter. As at least seven years are required to furnish the growth at which pearls may be sought with advantage[1], the inspection served only to suggest the prospect (which has since been realised) that in time the income from this source might be expected to revive;--and, forced to content ourselves with this anticipation, we weighed anchor from Condatchy, on the 30th March, and arrived on the following day at Colombo. [Footnote 1: Along with this two plates are given from drawings made for the Official Inspector, and exhibiting the ascertained size of the pearl oyster at every period of its growth, from the "spat" to the mature shell. The young "brood" are shown at Nos. 1 and 2. The shell at four months old, No. 3, No. 4. six months, No. 5. one year, No. 6, two years. The second plate exhibits the shell at its full growth.] The banks of Aripo are not the only localities, nor is the _acicula_ the only mollusc, by which pearls are furnished. The Bay of Tamblegam, connected with the magnificent harbour of Trincomalie, is the seat of another pearl fishery, and the shell which produces them is the thin transparent oyster (_Placuna placenta_). whose clear white shells are used, in China and elsewhere, as a substitute for window glass. They are also collected annually for the sake of the diminutive pearls contained in them. These are exported to the coast of India, to be calcined for lime, which the luxurious affect to chew with their betel. These pearls are also burned in the mouths of the dead. So prolific are the mollusca of the _Placuna_, that the quantity of shells taken by the licensed renter in the three years prior to 1858, could not have been less than eighteen millions.[1] They delight in brackish water, and on more than one recent occasion, an excess of either salt water or fresh has proved fatal to great numbers of them. [Footnote 1: _Report of_ Dr. KELAART, Oct. 1857.] [Illustration: PEARL OYSTER. 1, 2. The young brood or spat. 3. Four months old. 4. Six months old. 5. One year old. 6. Two years old.] [Illustration: THE PEARL OYSTER. Full Growth.]