72 PECTINID.E. 



prominent : ears long and drooping, nearly square-set, those 

 on the byssal side being the smallest, rounded at the corner ; 

 byssal notch slight: hinge-line straight, two-fifths of the 

 breadth of the shell : cartilage small : ligament so thin as to 

 be almost imperceptible : hinge-plate broad and smooth; trans- 

 verse rib slight and scarcely raised : inside pearly, minutely 

 striate lengthwise : muscular scars distinct. L. 0-285. B. 0-3. 



HABITAT : Sparingly occurring, although gregarious, 

 on all our coasts, in muddy sand at 2-82 fathoms. 

 Glacial deposits, Fifeshire (Fleming) ; Coralline Crag 

 (S. Wood). Its distribution extends from Finmark to 

 the ^Egean ; and both in northern and southern locali- 

 ties it appears to have a. considerable range of depth, 

 viz. 15-200 fathoms, Upper Norway, according to 

 M 'Andrew and Barrett, and 27-185 fathoms in the 

 ^Egean, according to Forbes. Norwegian specimens 

 collected by Professor Sars are of an extraordinarily 

 large size. 



The animal, as well as the shell, of this tiniest of 

 scallops 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 almost 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 specimen 

 measures only 0'35 by 0'375. The breadth invariably 

 exceeds the length. 



For the discovery of this species science is indebted 

 to the late Capt. 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.pygmceus of Von Miinster, P. mini- 

 mus of Sars, P. Actoni of Von Martens, and P. Foresti 

 of Martin. The P. Grcenlandicus of Sowerby (P. vitreus 



