VARIETIES OF OYSTERS. 185 



Barrett, and 27-185 fathoms in the JEgean, according to 

 Forbes. Norwegian specimens collected by Professor 

 Sars are of an extraordinarily lars;e size. 



J O 



The animal as well as the shell of this tiniest of scal- 

 lops is very lovely. If, when fresh caught, put into a glass 

 of sea-water, it flits about like a bat for a long time, and 

 then fastens itself to the side of the vessel by a fine and 

 atmost transparent byssus. After a while it slips its cable 

 and resumes its voyage of discovery, until it becomes 

 apparently exhausted by the fruitless search, and lies down 

 on one side. My largest specimens measure only 0.35 by 

 0.375. The breadth invariably exceeds the length. 



For the discovery of this species science is indebted 

 to the late Captain Laskey, although he described and 

 figured it from a right valve only, not having at that time 

 obtained a perfect specimen. It is the Ostrea tumida of 

 Turton, P. pygmaeus of Von Minister, P. minimus of Sars, 

 and P. Foresti of Martin. The P. G roe.nl andicus of Sowerby 

 (P. vitreus of Dr. Gray but not of Chemnitz) resembles the 

 present species in nearly every respect but that of size. It 

 may be an arctic variety of P. similis or (more probably) a 

 direct and "pur-sang" descendant from the original stock. 



B. Upper valve nearly flat and concave towards the 

 beak ; hinge-line ribbed obliquely. 



9. P. MAXIMUS, Linne. 



Ostrea jnaxima, Linn. Syst. Nat., p. 1 144. P. maximus, 

 F. and H. 2, p. 296, pi. 49. 



BODY pinkish-white above, and bright red or pink in 

 front : mantle variously marbled with brown, black, and 

 white : cirri on the inner margin of the mantle short, white, 

 and arranged in a single row ; those on the fixed or exterior 



