Two Indo-West Pacific species, mostly differing in colour, were confused under the name Calcinus gaimardii. The original species named by H. Milne Edwards (shield reddish brown at least on the anterior fifth), is redefined and compared to the other, C. morgani n, sp. (shield light cream or grey with darker patches anteriorly and laterally). A number of Indonesian specimens belonging to both species, often from the same locality, are reported. The general distributions of C. gaimardii and C. morgani n. sp. are discussed. They are sympatric over a large area, but it appears that C. morgani is more widespread. A second new species, C. areolatus n. sp., is described from Ambon and Sulawesi ; it differs from C. morgani mainly by the occurrence of brown spots throughout the length of second and third pereopods, not on dactylus and propodus only.
Decapoda, Coenobitoidea, Diogenidae, Calcinus, Indo-West Pacific, Indonesia.