Abstract
THE Marine Biological Report of the Province of the Cape of Good Hope (No. 4) for the year ending June 30, 1918, has recently been received. The report is signed by Prof. J. D. F. Gilchrist, and although it appears that his department has been greatly restricted by lack of funds, it is clear that much useful work was done during the year under review. It is well known that a valuable industry in canning and exporting the local crawfish has been developed successfully at the Cape in recent years, and perhaps the most interesting feature of the report is an account of the habits of the different larval stages of this crustacean. The first larva of Jasus lalandii is small, somewhat opaque, and swims at the surface by its feather-like antennae, the other appendages being folded close to the body and not used. This first stage, known as a "naupliosoma,"continues for only a few hours, when it passes into the flattened "phyllosoma "stage. The larva? in this stage are able to swim in a horizontal direction, but their natural habitat is still the surface waters. They were successfully reared, and after three or four days at most they passed into the third larval stage, in which they descend to the bottom and seek out the darkest corners. They then feed actively on the small animal and vegetable particles in the mud and sand, and are comparatively free from the attacks of their enemies. After undergoing a series of moults, which do not yet appear to have been followed in detail, the larva enters the "puerulus"stage, which has hitherto been found only close inshore.
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Fishery Investigations in South Africa. Nature 104, 615 (1920). https://doi.org/10.1038/104615b0
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DOI: https://doi.org/10.1038/104615b0