254 SUMMARY OF CUIIKENT KESEAECUES RELATING TO 



habitat, and some individuals were found to be positive after exposure to 

 strong light. When the Isopods were immersed in water they did not 

 respond. The negative phototaxis appears to be a factor in keeping 

 the land Isopods in a suitable habitat. Land Isopods are more definitely 

 negative to light than the fresh-water Asellus communis. J. A. T. 



' "^ Influence of Environment on Bosmina longirostris. — Otto 

 Haetmann {Arch. EnUcicldungsmech., 1016, 42, 208-21, 1 pi.). Many 

 differences are known among individuals of the same Cladoceran species, 

 e.g. Bosmina longirostris. Every basin with distinctive peculiarities 

 has distinctive forms. The author has reproduced these experimentally, 

 e.g. as regards shortening of the tactile antennae, by altering the com- 

 position of the medium, e.g. by adding minute quantities of chemical 

 reagents, such as bromide of potassium, phosphoric acid, and hydrate of 

 chloral. The " variations " are " modifications." J. A. T. 



Food of Pelagic Copepods. — Calvin 0. Esterly {Univ. California 

 PuUications, Zoology, 1916, 16, 171-84, 2 figs.). Oil-immersion 

 examination of the food canal showed cases of minute diatoms and some 

 other minute organisms. All were too small to be seized by the Copepod. 

 A current passes through the setse of the first maxillipedes, and very 

 minute particles are agglomerated into a pill which is ingurgitated by 

 the pharynx. ' J. A. T. 



Light-production in Cypridina hilgendorfi. — E. Newton Harvey 

 {Year-book, Carnegie Inst. Washington, 1918, 17, 154-7). In previous 

 papers the author described the substances photophelein and photogenin, 

 which must be present with water and oxygen to produce light (bright 

 blue luminescence in Cypridina). But photophelein includes two sub- 

 stances. There is a luciferin, analogous to that in Fholas dactylus ; it 

 is dialyzable and thermostable, and in presence of non-dialyzing and 

 thermolable lucif erase (photogenin) oxidizes with light-production. 

 There is, secondly, another substance, photophelein proper, which occurs 

 in many non-luminous animals, but in Cypridina assists in promoting 

 the lucif erin-lucif erase reaction. Oxy luciferin formed by oxidation is 

 readily reduced to luciferin again, which will again give light. The 

 reduction may be effected by reductases of muscle, liver, etc., or by 

 bacteria, or in other ways. Luciferin and oxyluciferin seem to have 

 identical chemical properties. They may be provisionally placed in a 

 new group of natural proteins on the borderland between the proteoses 

 and the peptones. Luciferase is a protein, and all its properties agree 

 with those of the albumens. J. A. T. 



Upper Cambrian Ostracods. — Frederick Chapman {Proc. Roy. 

 Soc. Victoria, 1918, 31, 108-12, 1 pi.). From the Upper Cambrian 

 Limestone of - South Australia a number of fossils were obtained — 

 namely, Leperditia tatei sp. n., L. capsella sp. n., and Isochilina sweefisp. n. 

 It is a striking fact with regard to the two species of Leperditia that they 

 represent Southern Hemisphere forms of two distinct types of the genus, 

 both of which are found in Canada. J. A. T. 



