LUTRARIA. 427 



other mollusks, and reveals its hiding-place." Mr. G. H. 

 King, of No. 190 Portland Road, lately kept a living 

 specimen in one of his tanks, among other interesting 

 things which this experienced naturalist dealer has ex- 

 hibited to the public. Poli's description of the animal 

 is very short: margin of the mantle flattened and 

 fringed ; tubes rather long, united throughout, and cir- 

 rous ; foot lanceolate. It goes by the name of " Schias" 

 at Granville, and is sold in the fish-market at Brest. 



Born described this species from a single valve, but 

 accurately and unmistakeably. It was named by Chem- 

 nitz " Mactra helva seu helvacea" scarcely a binominal 

 appellation. He seems to have occasionally exercised a 

 good deal of useless ingenuity in inventing new names, 

 even when he was aware of those given by the disco- 

 verers. Thus we have seen that the M. solida of Linne 

 became his M. vulgaris. The present species is the 

 M. Neapolitans of Poli. 



The M. fragilis of Chemnitz (M. . dealbata, Pulteney, 

 and M. Braziliana, Lamarck) is South American, and 

 not British. Turton's specimen (a single valve) is so 

 battered and antiquated that its exotic source may be 

 safely taken for granted, with a mental reservation or 

 doubt as to the correctness of his statement that it was 

 " dredged in the Channel, near Guernsea." 



Genus III. LUTRA'RIA *, Lamarck. PI. VIII. f.3. 



BODY elongated and somewhat cylindrical, compressed: 

 mantle thick : tubes very long, united almost to their extre- 

 mities and enclosed in one sheath ; orifices fimbriated. 



SHELL oblong, very inequilateral, widely gaping at both 

 ends, especially on the posterior side, slightly and concentri- 

 cally striated: beaks turned towards the anterior side and 



* Associated with the otter. 



