The gross morphology of foregut was investigated and described in detail for four freshwater crab species: a pseudothelphusid, Fredius reflexifrons (Ortmann, 1897) and three trichodactylids - Sylviocarcinus pictus (H. Milne-Edwards, 1853), Valdivia serrata White, 1847, and Dilocarcinus septemdentatus (Herbst, 1783). In general, the gastric mills of freshwater crabs showed a similar degree of complexity in relation to other marine species of Anomura and Brachyura previously described in the literature. However, significant morphological differences were observed among the analyzed species, as in ossicle numbers, features and connection types. A total of 38 ossicles were described for S. pictus and V. serrata and 37 ossicles for D. septemdentatus and F. reflexifrons, respectively. The latter species can be distinguished from the others by the presence of a wide cardiac sac resembling two sacs. Most of the ossicles were connected through a rigid connection, and few ossicles were fused. The degree of calcification varied little among the studied species. The differences found among the species suggest that the morphological aspects of the foregut may be useful in the identification of similar species.

São descritos e ilustrados em detalhes, os quatro estágios de zoea e um de megalopa do caranguejo Armases benedicti (Rathbun, 1897), a partir de larvas obtidas em laboratório. A média de duração de cada estágio larval foi 3, 2, 4, 4 e 13 dias, respectivamente. O período compreendido desde a eclosão até o surgimento do primeiro juvenil foi de 26 dias. Morfologicamente A. benedicti é muito similar às outras espécies do gênero, contudo, um pequeno espinho lateral é claramente observado na carapaça das zoeas desta espécie. Esta característica aparenta ser única dentre os Sesarmidae. Outra característica distinta desta espécie é a distribuição das cerdas do endópodo da maxila (2+2), o qual difere dos demais sesarmídeos que apresentam a distribuição (2+3), exceto para Sesarma tetragonum (Fabricius, 1798) o qual apresenta (2+2). Outras comparações morfológicas com trabalhos anteriores relacionados a larvas do gênero Armases Abele, 1992 são brevemente discutidas.

The four zoeal and one megalopal stages of the wharf crab Armases benedicti (Rathbun, 1897) larvae reared in the laboratory are described and illustrated in detail. The mean duration for each larval stage was 3, 2, 4, 4 and 13 days, respectively. The duration of the larval period from hatching to the first juvenile was 26 days. Morphologically, A. benedicti is very similar to the reported species of genus. However, a small lateral spine is clearly observed in the carapace of zoeal stages of this species. This feature appears to be unique among the family Sesarmidae. Another distinctive character for this species is the zoeal setation of the maxilla endopod (2+2) in which most of the sesarmids have setation (2+3) except for Sesarma tetragonum (Fabricius, 1798). Other comparisons with previous larval studies of the genus Armases Abele, 1992 are briefly discussed.

Pinnixa gracilipes Coelho, 1997 é um pequeno caranguejo pinoterídeo que vive em associação com Lepidophthalmus siriboia Felder & Rodrigues, 1993 no nordeste do Estado do Pará, Brasil. Larvas de P. gracilipes foram cultivadas em laboratório desde o nascimento ao estágio megalopa. O desenvolvimento completo durou cerca de 24 dias. O período médio de cada estágio foi 5, 4, 4, 5 e 6 dias, respectivamente. No presente trabalho, os cinco estágios zoeae e megalopa são descritos e ilustrados em detalhes. Comparações morfológicas com estudos anteriores sobre larvas da família Pinnotheridae são brevemente discutidas.

Pinnixa gracilipes Coelho, 1997 is a small pinnotherid crab living in association with ghost shrimp Lepidophthalmus siriboia Felder & Rodrigues, 1993 in the northeastern region of Pará State, Brazil. Larvae of P. gracilipes were reared in the laboratory from hatching to the megalopa stage. The complete zoeal period averaged 24 days. Mean duration for each larval stage was 5, 4, 4, 5 and 6 days, respectively. In the present study, five zoeal and megalopal stages are described and illustrated in detail. Morphological comparisons with previous reported works on Pinnotheridae larvae are briefly discussed.