COLLECTION OF SHELLS. 5l5 



rare. We have two species. The teredinae, 

 which form their tube in the interior of sub- 

 marine wood, are natives of the same country; 

 hut they thrive as well in our seas, particularly 

 on the Dutch coasts, where they do much mis- 

 chief to the dikes. The the family of the pho- 

 ladaria have the same habits, but they penetrate 

 into the hardest substances, such as limestone- 

 rocks and pebbles. They form two genera ; the 

 pholas, which has a white and often a very large 

 shell, and the gastrochcena, of which the shell is 

 small and rather rare. We have but two species 

 of this last. 



The solenacece live under the sand : we shall 

 particularize among them, the solen, vulgarly 

 called razor shell, of which there are nine- 

 teen species in the collection ; the panopcea , a 

 fossil shell found at Placentia in Italy; the ana- 

 tifice , very fragile and much esteemed shells. 

 The anat. subrostrata, the largest of the six spe- 

 cies we possess , comes from the seas of New 

 Holland. 



The family of the mactracea consists of seven 

 genera ; the most numerous is the mactra, of 

 which we have twenty-seven species. The 

 m. triangularis and the in. spengleri are very rare 

 shells. The genus crassatella was known onlf 

 in a fossil state when captain Baudin's expedition 



33. 



