ABSTRACT. The aim of the present study was to ascertain the size at sexual maturity in females of the crab Sesarma rectum Randall, 1840 by comparing gonadal maturity to morphologic maturity (using abdomen-width data). The relative growth of the abdomen was analysed for all growth phases (for each 3-mm carapace width size class), and the slopes of the separate allometric relationships were compared through analysis of covariance (ANCOVA) from log e -transformed data to detect changes in the level of allometry during ontogeny. The physiological size at maturity (gonadal criteria) was determined through a logistic curve, indicating the size at which 50% of females presented mature gonads (M 50 = 17.4 mm CW). The highest allometric levels occurred in growth phases 2 and 3 (body sizes ranging from 15 to 21 mm CW), indicating faster growth of the abdomen during those phases. Phases 1 (< 15 mm CW) and 4 and 5 (size classes above 21 mm CW) showed isometric growth. In the study area, a mangrove on the northern coast of the state of São Paulo, Brazil, individuals of S. rectum began to reach sexual maturity from 15 mm CW onward, when the slopes of the relationship of abdomen width to carapace width became positively allometric, indicating a differential growth rate. A gradual decrease in the slope, tending to isometry, occurred during ontogeny, as the animals became larger (older).

Specimens of the zipper sand skate Psammobatis extenta were collected in the region of Ubatuba o¡ the northern coast of the State of Sa‹ o Paulo, Brazil, monthly for one year (January^December 2000), at 25-to 40-m isobaths. A total of 123 individuals were caught. The total length (TL) of females averaged 224.6 mm, and of males 217 mm. The overall sex ratio was 1:1. Analysis of the length^weight relationship indicated the existence of positive allometry in females, and isometry in males. The length at onset of sexual maturity was determined for both sexes; females reached sexual maturity at smaller sizes than males (TL 50 ¼230.7 and TL 50 ¼237.7 mm respectively). Females showed functional parity of both ovaries and uteri. Females that were pregnant or were carrying vitellogenic oocytes were observed during nine of the 12 months of the survey, indicating a continuous reproductive cycle. Psammobatis extenta was most abundant from January to April, and again from June to October. Most individuals were collected at the 40-m isobath. Both adults and neonates were collected in the study area. However, adolescent skates were scarce, which either indicates di¡erential occupation of the area, or suggests that the shallow waters of the continental shelf are used as breeding grounds.

No presente trabalho, o número de ovos postos em desovas seqüenciais pelo caranguejo Aratus pisonii (H. Milne Edwards, 1837) foi quantificado com o objetivo de testar a hipótese de menos ovos serem postos em desovas consecutivas. Fêmeas ovígeras de A. pisonii foram coletadas em um manguezal (23º29'S, 45º09'W) localizado em Ubatuba, SP, Brasil no período de março de 2000 a março de 2003. Em laboratório, essas fêmeas foram separadas em dois grupos: Grupo 1, fêmeas incubando ovos em estágio inicial e, Grupo 2, fêmeas que realizaram desova subseqüente em laboratório. Ambos os grupos de fêmeas foram analisadas quanto ao número e tamanho dos ovos, peso seco da massa de ovos, peso seco do ovo individual e investimento reprodutivo (razão entre o peso seco da fêmea e o peso seco da massa). Vinte e sete fêmeas realizaram nova desova em laboratório. O intervalo médio entre uma liberação larval e uma desova subseqüente foi de 6,4 ± 5,6 dias. O número de ovos e o investimento reprodutivo não diferiram entre os grupos de fêmeas. Pequenas diferenças foram detectadas no tamanho e peso dos ovos, sendo que os ovos ovipositados nas desovas seqüenciais foram menores e mais pesados que os observados para as fêmeas do Grupo 1. A variabilidade do número de ovos produzidos por A. pisonii não pode ser atribuída a desovas consecutivas. Talvez o estado intrínseco das fêmeas é que some mais por essas diferenças na alocação de recursos.

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