PEARL AND PEARL-SHELL FLSHERIES. 



21 



proposed to distinguish it by tiiat of Mclcagrina nigro-uiarginata. It is an open question vvhetiier 

 the large Polynesian black-edged variety (commercially known as the " Tahiti shell ") must not 

 be regarded as specifically distinct from the smaller Australian form. It is, at any rate, 

 significant that in the equatorial region of Torres Strait, where the white shell attains its 

 maximum dimensions of a foot or more in diameter, the black-edged species never exceeds a 

 diameter of six or seven inches ; yet, among the South Sea Islands an (except for size) 

 indistinguishable form may equal the dimensions of the largest Torres Strait white variety. 

 The definition of the black-edged form as the type ol a separate species is, at all events for 

 the present, associated only with the medium-sized Queensland shell. 



A reference to the size and the fine quality of the pearls produced by Queensland mother- 

 of-pearl shells was made in a preceding chapter, p. 58, the reference being directly connected 

 with the examples photographically illustrated in Plate XXXVIl. There are herewith given 

 wood-block delineations of some half-a-dozen Torres Strait specimens of abnormal size, shape, 

 or composition, that fell within the author's notice during his recent Queensland journeyings. 



a 



QUEENSLAND PEARLS. 



N.'^TUR.VL-SIZED OUTLINE ILLUSTKATIONS OF REM.\RKAL1LE PEARLS OBTAINED FROM TORRES STRAIT. 



I. Large nodular black and white pearl ; weight, 84 carats or 336 grains ; the black portion composed of material 

 identical with that of which the hinge is constructed. This remarkable specimen is, or was originally, the 

 property of Mr. John Davis, the Mayor of Cooktown. 2. Large pear-shaped pearl; weight, 40 carats or i6o 

 grains ; the value of this specimen depreciated in consequence of a slight blemish on one side. 3. Perfect 

 spherical pearl; weight, 22 carats or 88 grains; the first price for which this pearl was sold was ^400. 4. Pear- 

 shaped pearl; weight, 6]{, carats or 28 grains; valued at ^100. 5. Irregular acorn-shaped pearl, the basal por- 

 tion, representing the cup, being of a dark-brown hue. 6. Conical or drop-shaped pearl, suitable for a pendant. 



In addition to pearls, some living organisms of interest are occasionally found within the 

 mother-of-pearl shells when freshly opened. One of these is a little brown spherical crab belong- 

 ing to the genus Pinnotheres, which very nearly resembles the mussel-inhabiting Pea-crab — Pinno- 

 theres pisuin of the British seas. A second Crustacean that occurs rather abundantly under 

 corresponding conditions, in living pearl-shells in Torres Strait, more resembles a little trans- 



