MOLLUSCAc, 135 



The term bone has been improperly applied to this com- 

 plicated plate ; " for," according to Mr. Hatchett, (Phil. 

 Trans, vol. Ixxxix. p. 321.) " this substance, in composition, 

 is exactly similar to shell, and consists of various mem- 

 branes, hardened by carbonate of lime, without the small- 

 est mixture of phosphate." 



The most remarkable species of this genus is the Sepia 

 officinalis, which is distinguished from the others by its 

 smooth skin. It inhabits the British seas, and although 

 seldom taken, its bone is cast ashore on different parts of 

 the coast, from the south of England to the Zetland isles. 



GENUS LOLIGO. Calamary. Sides of the sac only fur- 

 nished partially with fins. 



The suckers are disposed on the arms and feet in a 

 double row. The dorsal plate is flexible and corneous, im- 

 bedded in the substance of the sac, and is multiplied with 

 years. Dr. Leach has described three new species of the 

 genus Loligo, which were collected by Mr. Cranch during 

 the voyage to the Congo, in that unfortunate expedition 

 under the direction of Captain Tuckey. These species be- 

 long to a group which have the suckers produced into hook- 

 ed processes. In two of these species, L. leptura and 

 Smithii, the suckers on the arms, as well as the feet, are 

 produced into hooks, while, in one species, L. Banksii, the 

 feet only are armed with hooks.^ 



The same distinguished naturalist has instituted a new 

 genus nearly allied to Loligo, from two species collected 

 during the same voyage. The following characters are as- 

 signed to it. 



" GENUS CRANCHIA. Body oval, sac-shaped ; fins ap- 

 proximating, their extremities free; neck with a frenum 



