MONOCULUS. MONOCULUS. 
Generic Character. 
Pedes natatorii. 
Corpus crusta tectum. 
Oculiy plerisque, approxi- 
niati, testae innati. 
Feet formed for swimming. 
Body covered by a crust- 
aceous tegument. 
EyeSy in most species, ap- 
proximated, and imbed- 
ded in the shell. 
o F the jMonoculi by far the major part are very 
small water-insects, requiring the assistance of a 
microscope for the investigation of their particnlar 
organs: some however are so large as to require 
no very minute inspection; and one species in 
particular, (if indeed it can be allowed to stand 
with propriety in the genus) is of a size so gigantic 
that It is generally considered as the largest of the 
whole crustaceoiis tribe. This animal is the JMono- 
ciilus Polyphemus of Linnaeus, commonly distin- 
guished by the title of Molucca Crab or King- 
Crab. Specimens are sometimes seen of two feet 
in length, exclusive of the tail. It is a native of 
the Indian ocean, and is said to be generally 
found in’ pairs, or male and female swimming to- 
gether. The colour of the whole animal is a 
yellowish brown: the shell is very convex, rounded 
