ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 45 



Fauna of Water-pipes and Reservoirs. — R. Kirkpatrick (^The 

 Biology of Water ic or ka, British Museum (^Natural History)^ 1917, 

 2nd. ed., 1-58, 18 figs.). The fauna that may be associated with a 

 water-supply includes fixed and free-swimming Protozoa, the two com- 

 mon fresh- water sponges {Spongilla lacustris and Ephydatia fluviatilis), 

 species of Hydra, many kinds of worms, numerous Polyzoa, about a 

 dozen kinds of Molluscs, a few crustaceans and insect larvae, young eels 

 jand the like. In reservoirs there are sponges, Polyzoa, Entomostraca, 

 larvae of Okiro?iomus, and so on. The Algag and Bacteria are also dealt 

 with, and the various methods of securing purity in the water-supply. 

 The whole study is very interesting. J. A. T. 



Tunicata. 



Bactericidal Processes in Ascidia. — J. Cantacuzene (0. R. Soc. 

 Biol. Paris, 1919, 82, 1019-22). Specimens of Ascidia mentula were 

 inoculated with a mobile Bacterium isolated from the intestine of 

 Aplysia. The blood of the Ascidian is strongly acid, is very rich in 

 oxydase, and contains a great variety of amoebocytes. To begin with, 

 the circulating blood shows no other defence but intracellular digestion, 

 but after the sixth day there is very marked agglutination of the 

 Bacteria in direct contact with the amoebocytes. Some hyaline 

 amoebocytes give rise to a tenuous glairy substance which immobilizes 

 Bacteria ; others containing fatty substances arrest the Bacteria that 

 come into contact with them. The agglutination increases from the 

 sixth to the tenth day. The phagocytosis also continues with intensity ; 

 the infection is usually mastered. The acidity and oxidizing capactiy 

 of the blood are remarkably diminished soon after inoculation, but 

 re-appear as the Ascidian recovers. J. A. T. 



INVERTEBRATA. 



Mollusca. 

 a. Cephalopoda. 



Orthogenetic Development of Costsein Perisphinctinae. — Marjorie 

 O'CONNELL (A7ner. Journ. Set., 1919, 48, 450-60, 2 figs.). Using the 

 term orthogenesis to denote the fact of progressive change in one 

 direction in a succession of ontogenetic or phylogenetic stages, and not 

 as a term for a theoretical interpretation of the fact, the author 

 illustrates it in the ontogeny of the Jurassic Ammonite, Ferisphinctes 

 cubanensis, as regards the development of the cost*, and shows that the 

 stages in the single individual are characteristic of the adults of earlier 

 geological representatives of the genus. The definite direction seen in 

 the ontogeny is not a matter of individual growth, but is some tendency 

 inherent in the organism which leads to the same type of development 

 in related species and in ancestors and descendants throughout Middle 

 and Upper Jurassic time. J. A. T. 



