59 
aqueous plants. The eyes of lobsters are large, and 
singularly prominent; those of scorpions, minute : 
the latter are eight in number, and in position re- 
semble those of spiders. The greater number of 
animals possesses only two eyes: spiders have six, 
or more commonly eight. I know not any animal 
which possesses only one eye, although the ill-com- 
pounded name monoculus has been not quite cor- 
rectly given to certain apterous insects‘. The eyes 
of grylli and libellule, of wasps and of butterflies, 
are large and prominent; those of moths compara- 
tively small. Those of most coleoptera and aptera 
are small and fixed. The eyes of snails are con- 
spicuous at the extremity of their upper pair of 
flexible and retractile horns. The large eyes of 
sepiz or cuttle fish are said (by Shaw) to be strung, 
as pearls for necklaces, on the shores of Sicily, and 
in other maritime parts of the Neapolitan empire. 
In the numerous soft-bodied inhabitants of multi- 
valve and bivalve shells, eyes are not discoverable. 
Sensibility to the presence of light is unquestionable 
4 The cyclopes have two eyes, but so close together that a mi- 
croscope is required to perceive their division. Monoculus poly- 
phemus, or king crab, said by Linneus to be the largest of in- 
sects, is stated to have two pair of eyes; two on the sides of its 
shell, and two on the abrupt ends of two apparently rudimental 
claws. Over these the shell is diaphanous, elsewhere opaque. 
See a paper on the curious structure of the eyes of the monoculus 
polyphemus by Mr. André in Philosophical Transactions. The 
giant strombide, which inhabit the Caribbean sea, are said to 
have ‘“‘ eyes more perfect than those of many vertebrated ani- 
mals ; viz. a distinct pupil and a double iris, equal in beauty to 
those of birds and reptiles.’’ Zoological Journal, No. XIV. p. 172. 
