ABSTRACT
The original description of the progression and histopathology of Dermo has stood unchallenged without modification for almost 50 years. Exchange of research data and preliminary interpretation of results were shared to a degree unparalleled in invertebrate disease research. A long-time, concentrated investigation of diseases of the blue crab, Callinectes sapidus , and similar research on penaeid shrimp were begun in the early 1970’s. Useful information on diseases of other invertebrate taxa is, for the most part, fragmentary. Pseudocoelomate bilateria share the characteristic of eutely or cell constancy and do not undergo necrobiosis or cell renewal. Death in invertebrates is difficult to define and even more difficult to recognize because somatic death, or death of the entire organism, typically occurs only after necrosis, or cell death, of large areas of the organism. In controlled laboratory experiments and field exposures, pathological effects of the xenobiotic agent at the tissue level are of paramount importance.
