VARIETIES OF OYSTERS. 179 



never seen it perform such an extraordinary feat. The jet 

 of water would be at least fifty times the length of the 

 animal. 



A slight and pardonable liberty has been taken in 

 changing the original spelling of the specific name from 

 tigerinus to tigrinus. This shell was called P. parvus by 

 Da Costa, P. domesticus (used of course in the sense of 

 native) by Chemnitz, and P. obsoletus by Pennant. 



6. P. TESTJE, Bivona. 



P. Testa (Bivona), Philippi. Moll. Sic. i, p. Si, t. v. f. 17. 

 P. furttvus, Lov. Ind. Moll. Scand., p. 31. 



BODY pale yellowish white, faintly tinged with pink, 

 mottled with dark brown, speckled with flake-white, and 

 'barred transversely with 8 or 10 irregular streaks of dark 

 brown : mantle fringed with fine tentacles of different sizes, 

 which are delicately ciliated and curl about in every direc- 

 tion ; they are arranged in two rows, the outer tentacles 

 being much larger than those forming the inner row ; the 

 front edges of the mantle are folded inwards, and appear 

 to be microscopically striated in the line of the opening : 

 ocelli half as many only as in P. striatus, and consisting of 

 two rows ; those in the outer row are unequal in size and 

 irregularly distributed, one being in many cases (but not 

 invariably) placed at the base of each pallial cirrus in that 

 row ; those in the inner row are more numerous, much 

 smaller, and not always observable : foot cylindrical : gills 

 in two pairs, fan-shaped and exquisitely pectinated, some- 

 times brownish or pencilled in the middle. 



It flits or jerks about actively, like its congeners, and 

 occasionally moors itself by a byssus. The colour of the 

 soft parts is not less variable than that of the shell. When 



