428 SUMMARY OF CURRENT RESEARCHES RELATING TO 



peopled the deep sea before it acquired a low temperature. Another 

 part may be referred to a Tertiary migration from littoral regions at both 

 poles : the northern contingent derived from an ancient Mesozoic Medi- 

 terranean fauna, the southern contingent derived from an ancient 

 Pacific fauna. Another, but less probable, mode of origin would be a 

 direct migration from tropical littoral faunas. 



Slime-Formation in the Sea.* — C. Cori describes the occurrence 

 of immense quantities of slime in the Gulf of Trieste in the summer 

 of 1905. It was so marked that it lessened the number of pelagic 

 organisms, smothered many littoral forms, and fouled the nets of the 

 fishermen. It was mainly due to encysting Peridinege, and secondarily 

 to Bacillariaceae. 



Anhydrobiosis, Parthenogenesis, and Phototropism.f — G. Bohn 

 calls attention to the fact that Giard has induced artificial partheno- 

 genesis in the eggs of starfish by physical and chemical dehydration, 

 and subsequent exposure to the exciting action of the sea-water. So, 

 Bohn points out, there is physical and chemical dehydration in supra- 

 littoral animals, like Littorina rudis and Harpacticus fulvus, when the 

 tide is out, and an extraordinary excitation when the tide comes in 

 again. There is very marked negative phototropism ; there are ex- 

 tremely active movements which have an optic origin. There is an 

 established vital periodicity determined by the tides, for even in an 

 aquarium, although the desiccation or intoxication persists, the creatures 

 awake from their torpor, and with mathematical precision make for the 

 shaded regions. We do not follow the argument, but the author says 

 there is a complete parallelism between artificial parthenogenesis and 

 phototropism. 



Fauna of Natal. $ — Ernest Warren presents the first report of the 

 Natal Government Museum, which shows in the text and by the illustra- 

 tions what arrangements have been made to preserve and exhibit for 

 museum purposes the fauna and flora of Natal. The report, which says 

 much for the industry and though tfulness of the director, includes 

 catalogues of ethnological exhibits, and of the mammals, birds, reptiles,, 

 amphibians, fishes, invertebrates, fossils, etc. 



Peripheral Nervous System of Mammals.§ — E. S. London and 

 D. J. Pesker have investigated various embryos of white mice as regards 

 the nerve endings in striped and smooth muscle, and especially in 

 heart muscle. They describe the finer structure of the ganglion cells 

 of the heart, and the sensory cells of the inner ear. In the tympanal 

 wall of the cochlear canal the outer and inner hair cells develop as cells 

 pointed at the lower end. Gradually from the ganglion cells there 

 grow out spiral fibrils which are directed to the lengthening point of the 



* Archiv Hydrobiol. Planktonkunde, i. (1906) pp. 385-91. See also Zool. 

 Zentralbl., xiii. (1906) pp. 300-1. 



t Comptes Eendus, cxli. (1905) pp. 1260-2. 



% First Report of the Natal Government Museum, year ending December 1904,, 

 (Pietermaritzburg, 1906) 185 pp., 14 pis. 



§ Arch. Mikr. Anat., lxvii. (1906) pp. 303-18 (3 pis.). 



