Studies on the Development of the Crab Pugettia Quadridens (De Haan) : 1.HATCHING and Zoeae

Abstract

Majidae) has been described by AIKAWA ('29, p. 38 and 39), who obtained the larvae from the berried crabs. In the winter of 1969, the present writer had a chance to observe the development of P. quadridens collected on the Pacific coast of the southwestern Hokkaido, North Japan, and came to a conclusion that his first zoea obtained shows many differences in structure in comparison with that of AIKAWA. As the crabs studied by AIKAWA were collected on the Pacific coast of the southern Kanto District, .Middle Japan, the differences between the characters of the bot~ larvae may be either due to the environmental or to the genetical differences. The present paper deals with the development of Pugettia quadridens from northern Japan, especially regarding the hatching of eggs and characters of the pre-and first zoea. The crabs for the present observation are stocked in the Zoological Institute,

Mechanisms of crustacean egg hatching: Evidence for enzyme release by crab embryos

“…Gray 1942, Wear 1967, Suk6 1969, Iwata 1970, Pandian 1970, Winnicki and Slomianko 1970, implying an osmoticallydriven increase in water content (Davis 1968, Pandian 1970. For N. sayi and S. cinereum, egg volumes increased most rapidly during mid-stages of development, and for U. pugilator during early and mid-stages of development, with a distinct slowing of volume increases during the last several days before hatching for all three species.…”

“…Mechanical movements of the embryos aid osmotic hatching of Callinectes sapidus (Davis 1965), and Pilurnnus lurnpinus and P. novaezealandiae (Wear 1967). Iwata (1970) described simple mechanical hatching (by embryo movements) for the crab Pugettia quadridens, although an osmotic component is also likely since an increase in egg size during development was observed. For all crustaceans which carry their eggs until hatching, such as crabs and lobsters, abdomen pumping by the female [included in Pandian's (1970) Category 3] probably also facilitates egg hatching.…”

Morphological features of the larvae of spider crab Pugettia quadridens (Decapoda: Majidae) from the Northwestern Sea of Japan

“…Within the genus Pugettia the larval development has been described, in greater or lesser detail, for P. quadridens [6,8,9,12,15], P. intermedia [8,9,15], P. insica [12,15], P. similis [15], and P. marissinica [8,9]. The structure of zoea I and megalopa of P. quadridens has been described in most detail in the paper by Ko [8].…”

“…In the literature there are detailed descriptions of stages zoea I and megalopa, obtained under laboratory conditions [8,9] and incomplete descriptions of the stages of prezoea and zoea II [6,12,15].…”

“…The larvae of this species are briefly described from plankton samples collected in Sagami Bay [12] and larvae reared in culture [6,15]. In the literature there are detailed descriptions of stages zoea I and megalopa, obtained under laboratory conditions [8,9] and incomplete descriptions of the stages of prezoea and zoea II [6,12,15].…”