ORIGIN OF THE NAME 5) 
of an extensive class will be largely descriptive, because 
many features of wide range and great prominence are 
likely to be missing in outlying and erratic members of 
the group, and these consequently have to be passed over 
unnoticed, in favour of less conspicuous, and of alternative, 
or even of negative characters. 
The name Crustacea is a Latin word of old standing. 
Another and probably the original form of it is Crustata. 
The animals clothed in a crust, a covering of more or less 
flexibility, were distinguished by the ancients from the 
Testacea, in which the test, as in the example of an oyster- 
shell, is hard and rocky, and like a potsherd more ready to 
break than to bend. Dr. Johnson was of opinion that if 
the terms of natural knowledge were extracted from Lord 
Bacon’s works, few ideas in that branch of learning would 
be lost to mankind for want of English words in which 
they might be expressed.' Modern science would be much 
hampered by such a limitation of its verbal resources. 
Johnson's own dictionary during the last century does not 
recognise the substantive, a crustacean. The adjective, 
crustaceous, it thus defines: ‘ Shelly, with joints; not tes- 
taceous; not with one continued, uninterrupted shell. 
Lobster is crustaceous, oyster testaceous.’ The same dic- 
tionary defines and illustrates the word crab as follows: 
‘ A crustaceous fish. 
‘Those that cast their shell are, the lobster, the crab, 
the crawfish, the hodmandod or dodman, and the tortoise. 
The old shells are never found, so as it is like they scale 
off and crumble away by degrees.—Bacon’s Natural History. 
‘The fox catches crab fish with his tail, which Olaus 
Magnus saith he himself was an eye-witness of.—Derham.’ 
Shellfish, crayfish, and crawfish, are expressions still in 
use, although the term crab-fish is no longer in fashion. 
The uncritical ages had a tendency to regard as fish most 
animals which came out of the sea, and a story is told of 
a cook who persuaded her Hebrew mistress that a sucking 
pig became for all practical purposes a fish by being made 
‘See A Dictionary of the English Language. Preface. Eighth 
Edition, 1799. 
