SHELLS. 105 



tribes which inhabit the Indian seas. Of the land and 

 fresh-water skells belonging to the trachelipodous family- 

 little is known ; and we may conclude our remarks on the 

 univalve shells by mentioning the Umbrella Indica, which 

 resembles an expanded parasol, and Patella granatina and 

 tcstucUnana, species of a similar form. 



The conchifera or bivalve shells are usually le^s nume- 

 rous in collections than the univalve, but a large proportion 

 of those known to naturalists is from India. The beautiful 

 and singular Sfondyli, various Pedcns, Peda, Avicula, 

 Mallei, and others of the family of Malleaceaj, of which 

 the most remarkable is the Melcagrinamargariiifera,yN\ach. 

 furnishes the mother-of-pearl of commerce, are natives of 

 the Indian seas. Ostrca folium grows on the roots of the 

 mangrove and other littoral trees. Tridacna gigas, the 

 largest shell known, of which individuals have been found 

 to weigh from 400 to 500 pounds, occurs in the Indian and 

 Chinese seas. A large valve of this shell, presented by the 

 Venetians to Francis I. of France, is used as a baptismal 

 font in the church of St. Sulpice in Paris. The fresh-water 

 shells of India are as yet little known ; but although the 

 genera Unio and Anodon have their finest representatives 

 in the rivers and lakes of America, the species of these 

 genera that have been brought from the East give promise 

 of an ample store to reward the labours of scientific in- 

 quirers. There are many beautiful species of Cardita, Car- 

 dmm, Tcllina, Mactra, Mya, Solcn, and Pholas ; but we are 

 unable to communicate any information regarding their his- 

 tory which would interest the general reader. The allied 

 genera Venus and Cytkerca, named after the goddess of 

 beauty, whom the poets inaptly feigned to have emerged 

 from the sea, are plentiful in all countries ; but many of the 

 Indian species, such as V. lilerata, puerpera, Malabarica, 

 and C. tigerina, and erycina, are peculiarly beautiful. With 

 the Aspergillum Jaranum, a tubular shell, having a disk 

 surrounded by fimbriated rays, so as to resemble the pipe 

 of a watering-pail with the water issuing from it, we shall 

 conclude our necessarily brief enumeration. A few words, 

 however, will not be misbestowed on the pearl-fishery. 



The pearl-fisheries of Ceylon are among the most noted. 

 The most skilful divers come from CoUesh on the coast of 

 Malabar, and some of these are alleged to have occasionally 



