54 



one becomes formed at the raargin. The SiUquaria presents a similar 

 modification of structure, and it has been also considered that the 

 slit in Pleurotoma is in some measure analogous. 



The internal surface of the ' Ear Shells ' is lined with a bright 

 pearly nacre, which in most species is of remarkable iridescent bril- 

 liancy, glowing \vith all the colours of the rainbow ; the attention 

 mušt, however, be directed to the outer coating of the shell, for the 

 discrimination of species, and it is with this vie\v that the figures iu 

 the foregoing monograph are devoted mainly to external sculpture. 

 There is certainly a striking variation of character in the nacre of 

 different species, but the pattern of the inner surface is merely an 

 indentation of the outer. The number of perforations varies in dif- 

 ferent species, but may be said to coįrespond in different indi\dduals 

 of the sarae species ; where an exception occurs, it is that there is 

 sometimes one, or at most two, less in the adult than in the young 

 statė ; that is, when the animal arrives at maturity it continues to 

 stop up one or two of the perforations in advance of any ne\v one. 



It is a curious circumstance in the geographical distribution of the 

 Haliotides, that few, if any, are to be found where Chitons abound ; 

 as if they exchanged places to a certain extent in the two hemi- 

 spheres. There are a fe\v species from California, but along the 

 western coast of South America, \vhere Chitons are most abundant, 

 not any are found, and only one small species, the H. pulcherrima, 

 at any of the islands of the Pacific. They inhabit the coasts of 

 China, Japan, Ceylon, Mozambiąue, Cape of Good Hope, Borneo, 

 and the Philippine Islands ; but the greater number of species. and 

 the most remarkable, are from New Zealand and the continent of 

 New Holland, displaying all thė peculiarity of design which invariably 

 characterizes the fauna of those isolated regions. With the weU- 

 kDOwn Haliotis iuberculata of the Channel Islands, all are familiar. 

 It is, however, a circumstance worth noting, that although such near 

 neighbours, and comparatively abundant, especially at the island of 

 Jersey, it is rarely coUected on the coast of England. 



The Haliotides are found at low water, attached to the under sur- 

 face of masses of stone, and they fix themselves with great force to 

 the rocks, by suction, on the least alarm. 



/3.'9 Haliotis splendens. Hal. testd ovatd, convexo-depressd, undique 

 'f^ ( spiraliter liratd, liris crebris regularibus subobtusis, nonnullis aliis 

 latioribus ; foratninibus ųuinis perviis, ejctus <Ei~ugini-viridescente, 

 articulis albicantibus prope spiram interdum ?iotatd, epidermide 

 fibroso fusco indutd, inius cceruleo viridique, nigricante nebulatd, 

 pulcherrinie iridescente. 

 Hab. California. 



Haliotis Japonica. Hal. testd ovato-oblongd, suhplanulato-con- 

 r.'[ vexd, liris tenuibiis cequalibus spiraliter funiculatd, concaitrice 



mgoso-plicatd, plicis conspicuis lamelleeformibus irregularibus ; 



foruminibus quinis senisve perviis ; luteo olivaceo-fusco viridique 



undique pulcherrinie varieyatd. 

 Hab. Japan ; Dr. Siebold. 



