Decapodan

However, no decapodan crustaceans have yet been found in any of the numerous abyssopelagic and bottom samples from depths greater than 6,000 m.

The decapodan crustaceans are a large and diverse group of primarily marine animals.

Based on the different results given by various authors, on personal communications from colleagues and on personal observations, the crucial developmental steps in the formation of the nervous system in decapodan and octopodan cephalopods are reviewed.

The shrimp is, of course, a crustacean, a cousin, many times removed, of the crab and the lobster, and the famous crayfish, of whom Professor Huxley has written so admirably and exhaustively; but we need not dwell on the fact, or generalise him at length into the macrourans and decapodans.

The first morphological study of HPT in the crayfish, Astacus, and several other decapodans was made 100 years ago (Cyebitm 1893), and HPT of many crustaceans have been investigated later mainly by means of light microscopy (for reviews see Johnson, 1980; Bauchau, 1981).

These studies are important from biological aspects of the decapodans.