CEPHALOPODA, OR CUTTLE-FISHES. 357 



Of the secondary services rendered to man by the Molluscs we know but little, owing 

 to the localities in which the greater number of species live, their nocturnal or darkness- 

 loving habits, and their extreme dislike to intrusion. Several species, such as the pholas 

 or burrowing shell, and the teredo, so notorious as the shipworm, are well known to be 

 actively injurious to man, by destroying the foundations on which his edifices are built, 

 or the vessels in which he trusts his life and property to the waves. Yet even these 

 insidious enemies may have their uses to man, and by destroying the wrecks on which 

 many a noble vessel might be driven and share the same fate, may be the salvation of 

 costly property and invaluable lives. 



As to those which are known to be directly useful to mankind, it will be sufficient to 

 give a brief enumeration at present and to mention particulars when we come to the 

 individual species. 



Usefulness to man is, when reduced to its essence, the capability of affording him 

 food, and therefore the edible species must take first rank as regards use. The oyster is 

 familiarly known to rich and poor, the latter being often more practically cognizant of 

 its value than the former. It affords at once a refined luxury and a health-giving nutri- 

 ment ; it can be eaten uncooked, or opens a wide field for culinary art ; and it has the 

 farther advantage of being very plentiful, very cheap, very accessible, and very easily 

 preserved in a living state until needed. The mussel is another largely consumed Mol- 

 lusc, especially among the lower classes who cannot afford to buy oysters ; and in some 

 parts of the world is cultivated and bred in millions, the ever-increasing numbers, together 

 with the peculiar accommodation which they require, threatening to obliterate many a 

 natural harbor, and causing a well-grounded apprehension among ship-owners that their 

 vessels may be deprived of their accustomed refuge by means of this simple 

 Mollusc. 



The scallop again, with its classically famous shell and coral red foot, is another of the 

 edible species, as is the cockle, another well-known bivalve of our coasts. Some of the 

 foreign bivalve Molluscs are considered as very great delicacies, among which the clam 

 takes a very high rank. There is also the huge giant clam, formerly rare, but now per- 

 fectly familiar ; which has to be cut away from the rock by hatchets, and whose contents 

 are equivalent to a large round of beef, very well flavored, but rather tough and stringy. 



The single-valved species furnish many edible examples, such as the whelk and 

 the periwinkle, so largely consumed by the poor, and even the cuttles are capable of 

 affording a tolerably good repast when properly dressed. As a general rule, however, 

 the bivalves are most esteemed, as they are not so fibrous in texture, and therefore not 

 so tough as the univalves. 



The shells of the Molluscs are also of much service to mankind. Putting aside the 

 well-known money cowry, perhaps the most infinitesimally divided currency in the 

 world, many species are of exceeding value for the materials furnished by their shelly 

 coverings. Some species, where the shell is of that lovely nacreous nature which we 

 popularly term mother-of-pearl, are extensively employed in the manufacture of " pearl " 

 buttons, handles to pocket-knives, ornamental utensils, and in the inlaying of costly 

 furniture ; and even pearls themselves, the most precious offspring of the ocean, are 

 composed of the same substance as the nacreous coating of the shell ; other shells are 

 largely used in the manufacture of cameos, their alternate coats of creamy white and 

 rich red or warm brown giving beautiful artistic effect when skilfully handled. 



In former days, one of the univalve shells, known now as the purpura, and little 

 heeded except by the owners of marine aquaria, was employed for the purpose of pro- 

 ducing the celebrated purple of the ancients, which none but the imperial family were 

 permitted to wear. 



Having now taken a superficial glance at the Molluscs and their uses, we will pro- 

 ceed to the description of individuals, and examine closer into details. 



THE highest of the molluscs are those beings which are classed together under the 

 title of CEPHALOPODA. This is a term derived from two Greek words, the former signify- 

 ing a head, and the latter a foot, and it is applied to these creatures because the feet, or 

 arms as they might also be called, are arranged in a circular manner around the mouth 



