Vol. 9Q, No. 3 December, 1950 THE BIOLOGICAL BULLETIN PUBLISHED BY THE MARINE BIOLOGICAL LABORATORY SOME OBSERVATIONS ON A LUMINESCENT FRESHWATER LIMPET FROM NEW ZEALAND BERNARD J. BOWDEN University of Otat/n, Duncdin, New Zealand Iii view of the statement of Harvey (1940) that ". . . luminous animals are practically entirely marine or terrestrial. No examples of freshwater luminous or-ganisms are known except bacteria and an aquatic glowworm . . .," the luminous properties of the New Zealand freshwater mollusc, Latia ncriioides, would appear to be a unique and surprising phenomenon. This, together with the fact that, apart from the cephalopods, only three luminescent species of molluscs have been hitherto recorded (Harvey, 1940) is sufficient justification for a full investigation of the ap-parently exceptional properties of this freshwater limpet. Latia is a monotypic genus restricted to the North Island of Xew Zealand. It belongs to the family Ancylidae in which no other luminescent forms have been re-corded. The two other New Zealand species (Gundlachia neozelanica and G. lucasi} are certainly not luminescent. The luminescence of Latia was first recorded by Suter in 1890 and again re-ferred to in his comprehensive Manual of New Zealand Mollusca (1913). Al-though the phenomenon is well known to many New Zealanders. its nature and mechanism have never been studied. It was with this end in view, therefore, particularly in the light of modern re-searches in the field of bioluminescence, that the present investigation has been undertaken. MATERIAL AND METHODS Specimens of Latia ucritoides were collected near Auckland in December, 1 ( '4 (| , and were immediately placed in Benin's fluid. Subsequently during the investiga-tion, living specimens were obtained in May, 1950, for experimental and histological purposes. It was found that these animals remained alive in the laboratory for more than three weeks if placed in brown glass bottles in the dark, whereas if kept in white glass bottles and exposed to the light they died within a day or two. In order to contrast the histological structure of Latia with that of an allied non-luminescent form, specimens of Gundlachia Incasi were collected locallv and sub-mitted to simliar histological procedures. Luciferin-luciferase reaction. Three animals were shaken in 10 ml. of wnnr in a test-tube at room temperature for 10 minute.s. The solution was then de-373
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