Because crustaceans are the most morphologically diverse group of animals on the planet, it comes as no surprise that there exists a huge number of morphological terms that are being used, or that have been used in the past, to describe them. As far as I have been able to determine, there is no single, standard glossary that is widely accepted. This is in part because different terms may mean different things for different groups of crustaceans, and in part because many existing glossaries tend to deal with selected subgroups or local faunas rather than with the taxon as a whole. More general glossaries do exist, and include McLaughlin's (1980) book on crustacean morphology and the glossary in the Treatise on Invertebrate Paleontology (Moore and McCormick, 1969), upon which McLaughlin's glossary seems to have been largely based.
The following glossary includes terms and their definitions taken verbatim from a variety of sources. In all cases, the reference is given in brackets [ ] following the definition. In cases where the same term is defined in slightly different ways, both definitions are given and both references are listed. If the definitions are identical, I have simply cited both references after the definition. The references also include the name of the group or groups of crustaceans with which that reference primarily deals. For example, the terms taken from Williams (1984) deal only with the Decapoda, specifically those of the east coast of the United States, and this is so indicated. In some publications, the glossary also contains more adjectival terms and non-morphological entries, in addition to the strictly descriptive terms. I have opted to list everything found in the original publication, so that you will occasionally find unusual entries that seem to deal not with crustacean morphology in general but with descriptive terms or even more specialized topics (e.g., "Moult to puberty").
References to figures refer to original illustrations in the original publications, and not to any figures in this computer file. Perhaps some day we will be able to add appropriate figures to this file as well, as in some cases the figures are much more clear than the verbal definitions given.
Please be sure to cite the original source of the definition, and not this electronic file, as your source for these definitions.
I have not made any attempt to correct definitions, grammar, or spelling, preferring instead to list each entry as it originally appeared without inserting my own biases or judgment. An obvious exception with regard to biases is that my specialty is the Decapoda, and so initially most terms will have been taken from publications on this group. I hope that as time goes by and more definitions are received by other workers in the field, this bias will correct itself.
Some descriptive adjectival terms are included here as well, and definitions for some of these have been taken from the American Heritage Dictionary of the English Language, third edition [AHD].
If you are aware of other publications that contain good glossaries for crustaceans, please let us know so we can add them to our list.
Corrections? Additions? Comments? Please send them to me. I promise to at least consider them.