41 



very immature state of growth, and ou arriving at maturity, another and 

 richer layer of the same pattern is superimposed upon the former, which in 

 most specimens may be faintly seen beneath it. Another exception occurs 

 in the C. carneola, ventriculus, arenosa, sulcidentata, and one or two others ; 

 in these species the dorsal surface has no ornamental layer of pattern on 

 arriving at maturity ; the calcifying energies of the mantle, at an advanced 

 stage of growth, are directed exclusively, and with more than usual force, 

 to the thickening of the sides of the shell, and it is mostly accompanied 

 with a dull deposit of sand-like dots or striae. 



The Cypraa present two very distinct groups; the larger species in 

 winch the surface of the shell is highly enamelled, and the smaller species in 

 which it is disposed in grooves and ridges, of a more opake character and 

 more delicate texture. They offer little variety of form, but a diversity of 

 colouring; and among them are several very distinct and characteristic 

 species of unusual rarity, which our country can alone boast of possessing. 

 Of these the Cypmm princeps and leucodon, in our national collection, are 

 perfectly unique ; it seems curious that nature should not have exercised 

 her accustomed prodigality in the perpetuation of these species, for instead 

 of being the remnants of an extinct group, they appear to be the solitary 

 instances of a creation possessing an exuberance of character quite unap- 

 proached by any other species. They are both in the finest possible condi- 

 tion, and may certainly be regarded as the most valuable shells yet dis- 

 covered. The next in value are the C. Broderipii and guttata; of the 

 former, three specimens are known, two of which are in tins country ; of the 

 latter, five, of which we possess four. Of distinguished rarities of smaller 

 size may be mentioned C. Cumingii, Saula, xanthodon, similis, contaminata 

 and fusco-dentata, all in our collections. 



There is little to be said on the geographical distribution of the Cowries 

 except that they are mostly tropical. Only one or two very small grooved 

 species are found on our own coast, and none larger than C. lurida in the 

 Mediterranean. The C. Scottii may be quoted as a fine example of the 

 New Holland region, and the C. aurantium (the orange Cowrey), of the 

 Pacific. The C. pantherina is brought in great abundance from the Eed 

 Sea, but the greater portion of the species are from Mauritius, Ceylon, and 

 other parts of the eastern world. 



Species. 



1. Adamsoni, Gray. 5. annulata, Gray. 9. arenosa, Gray. 



2. albuginosa, Mawe. 6. annulus, Linn. 10. Argus, Linn. 



3. Algoensis, Gray. 7. Arabica, Linn. 11. asellus, Linn. 



■i. angustata,' Gray. 8. Arabicula, Lam. 12. aurantium, Mart. 



