above the level of the back; but generally it seeks an elevated position. We usually see it in the morning perched on the summit of some one of the more bushy weeds in the Aquarium, as the Chondrus or Phyllophora rubens, where it has taken its station during the night, the season of its chief activity, as of most other Crustacea. It interested me much to see it climb: seizing the twigs above it by stretching out its long arms alternately, it dragged up its body from branch to branch, mounting to the top of the plant deliberately, but with ease. While watching it I was strongly reminded of the Orang-otan at the Zoological Gardens; the manner in which each of these very dissimilar animals performed the same feat was so closely alike as to create an agreeable feeling of surprise.
This circumstance led me to think of another; the resemblance was not only in habit, but in conformation also; viz. in the great length of arm. This is obviously an adaptation for climbing in the Quadrumane as well as the Crustacean; and a few examples occured to my remembrance in which a similar structure is associated with the like habit. All the Monkey tribe, for instance; and the Sloths of South America, which are almost exclusively arboreal, have the anterior limbs excessively long. Many of the Longicorns among beetles are remarkable for their developed arms, and these are essentially tree-insects. Again, among the Spiders, the perpendicular web-makers as Epeira, Tetragnatha, &c., which run to and fro on the tracery of their slender lines, like seamen manning the shrouds on a fleet gala-day,—have the anterior legs much elongated; while the genera which live on the ground or on fixed
