Abstract
FURTHER reports on material collected by the British and Australian Antarctic Expeditions have been received. The Chaetognatha of the Australian Expedition have been described by Prof. T. H. Johnston and Mr. B. B. Taylor, systematic accounts of the Crustacea of the British (Terra Nova) Expedition are given by Mr. R. W. Barney on the Ostracoda, and on the Tanaidacea and Isopoda by Dr. W. M. Tattersall. Dr. H. M. Woodcock and Miss Olive Lodge describe the collection of parasitic protozoa, which consists of only three species—a new species of the flagellate genus Cryptobia, a new species of Gregarine (Selenidium), and a ciliate. This ciliate, for which a new genus (Hæmatophagus) is created in the family Stentoridæ, is parasitic on the baleen plates of the humpback whale, and feeds exclusively on the whale's red-blood corpuscles. It reaches a length of 1-1.5 mm., and secretes a delicate transparent tube, up and down which it moves; when feeding the oral end of the ciliate may project from the tube. The redblood corpuscles are directed into the mouth by the adoral zone of strong cilia fused into membranellæ, pass into the protoplasm, and become enclosed in food-vacuoles. The larger vacuoles may contain numerous corpuscles which become compressed, and, owing to the dissolution of the envelope of the corpuscles, the haemoglobin-containing substance of all the red cells in the vacuole merges into one homogeneous mass. As digestion proceeds the vacuoles pass gradually backwards, and pigment—agreeing in appearance with melanin—is formed on the outside of the vacuole. Hæmatophagus is unique among ciliates in producing melanin as a result of the digestion of hæmoglobin. This pigment tends to accumulate in the hinder half of the body, and the authors find evidence that when the organism is full-grown the pigment is got rid of by casting off that portion of the body prior to the commencement of the resting, multiplicative phase. How the blood of the whale becomes available to the ciliate has not been established.
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Marine Invertebrates. Nature 109, 530–531 (1922). https://doi.org/10.1038/109530b0
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DOI: https://doi.org/10.1038/109530b0