IANTHINA. 457 
view, on the plea that one intermediate family would be less 
repugnant to the feelings of conchologists, and even of some 
malacologists, than the adoption of five families, or the creation 
of five sections of essentially the same malacological structure. 
However great may be the disapprobation of naturalists at 
these changes, we feel it to be our duty to see that nature is 
satisfied before conchological hypothesis, and we fearlessly 
invite malacologists to point out a more natural site for these 
creatures, than as a united anomalous group, immediately 
abutting on the Muricidal tribes. 
This family will conspicuously illustrate the great advan- 
tage, nay even the triumph, of malacological facts over con- 
chological considerations, and point out the little reliance to 
be placed on the form of the hard parts as distinctive charac- 
ters. What conchologist would have ventured to associate 
these anomalous genera in the same circle? Conchology 
could never have given to these singular objects an appro- 
priate constitution : without the assistance of malacology they 
would for ever have remained a nomadic tribe, and indefinitely 
the sport of hypothesis. 
IANTHINA, Lamarck. 
This singular genus appears not to be indigenous to any of 
the coasts of our globe ; it has a truly oceanic habitat amidst 
the mighty waters of the Atlantic and Pacific ; but the various 
species are occasionally wafted to the different shores of the 
world. More than twenty years ago, many of the Janthina 
communis were brought to us alive, though collapsed, collected 
on the South Devon coasts ; but I believe none have appeared 
since in those localities. 
This genus has long caused embarrassment to naturalists, 
and is still a source of difficulty in regard to the structure of 
the animal and its natural position ; but I think the obstacles 
to a true determination will disappear on attentive consider- 
ation. The great stumbling-block is the float, as it is called, 
or vesicular mass attached to the foot, which has been con- 
sidered an hydrostatic apparatus. This idea is erroneous: 
