A survey of literature on fossil anti living crustacea fails to uncover a single reported case of unquestioned dwarfing. The molt stages of crustacea introduce a factor that is not ordinarily involved in the study of other invertebrates. Ostracodes pass through 7-9 molt stages. lt is conceivable that a group of molts could be misinterpreted as "dwarfing." An investigation concerning dwarfing in trilobites failed to uncover any evidence which would indicate the existence of such a fauna. The crustaceans are normal in dwarfed faunas because they were free swimming forms and lived in that portion of the water which had a normal pH. Whereas, the dwarfed forms were bottom dwellers that lived in an environment where the pH was low and the H 2 S high.