THE GASTEROPODS. 227 
slit on the sides, and a shell slit in a corresponding manner; CLEOvORA, 
the Cleodores, are like the preceding genus, only their shell is not slit 
along the margin. 
Some of these little animals are of a beautiful rose color, and others are 
blue and violet, variegated with spots of red. 
Godwin Austen describes the Pteropods as “the winged insects of the 
sea, reminding us, in their free-circling movements and crepuscular habits, 
of the gnats and moths of the atmosphere ; they shun the light, and if the 
sun is bright, you may look in vain for them during the livelong day — as 
days sometimes are at sea; a passing cloud, however, suffices to bring some 
Cleodorwe to the surface. It is only as day declines that their true time 
begins, and thence onwards the watches of the night may be kept by observ- 
ing the contents of the towing-net, as the hours of a summer day may be 
by the floral dial. The Cleodore are the earliest risers ; as the sun sets, 
Hyalea gibbosa appears, darting about as if it had not a moment to spare ; 
and, indeed, its period is brief, lasting only for the Mediterranean twilight. 
Then it is that Hyalea trispinosa and Cleodora subula come up; Hya- 
lea tridentata, though it.does not venture out till dusk, retires early, 
whilst some species, such as Cleodora pyramidata, are to be met with only 
during the midnight hours and the darkest nights. This tribe, like a higher 
one, has its few irregular spirits, who manage to keep it up through the 
whole night. All, however, are back to their homes before dawn surprises 
them. 
CLASS HI. THE GASTEROPODS. 
This numerous class, well represented by the Snail and Slug, is interest- 
ing from the exceeding beauty of the external covering which many of the 
genera provide for their protection. The greater portion of the sea-shells 
which adorn our cabinets are the productions of the Gasteropods. No archi- 
tect ever constructed such magnificent and elaborate palaces, and no artist 
ever blended such rich and glowing colors, or enlivened his works with tints 
of such exquisite delicacy. 
The animals of this class generally creep upon a fleshy disk under the 
belly, whence the name (rasteropods — Stomach-footers. The back is cov- 
ered with a cloak, of greater or less extent, and of a various figure, which 
secretes a shell in the greater number of the genera. Their head, placed in 
front, is more or less distinct, according as it is more or less drawn in under 
the cloak. It is furnished with tentacula of comparatively small size, and 
which do not encircle the mouth, their number varying from two to six, 
although sometimes they are absent. They are organs of touch and smell. 
