RECENT ADVANCES IN SCIENCE 53 



Regeneration of Tubularia supported by facts?" Jour. Exp. 

 Zool. vol. xxvi. No. 2, July 191 8). The principal evidence 

 adduced by Child was that if a polyp was cut into two and 

 decapitated, the oral end would grow a new head more quickly 

 than the basal end, but the present author by means of further 

 experiments of the same sort claims that this is not the case 

 and that the two ends can regenerate a head at equal speeds. 



Gatenby in a paper on " The Cytoplasmic Inclusions of 

 the Germ-Cells : Part 3, The Spermatogenesis of some other 

 Pulmonates " (Quart. Jour. Micro. Sci. vol. lxiii. Part 2, August 

 191 8) continues his investigations into the behaviour of certain 

 bodies appearing in the cytoplasm during the processes of 

 maturation of the spermatozoa in the pulmonate Mollusca. 

 A very useful inclusion in the paper itself is a discussion of the 

 terminology that has been employed by various writers and a 

 glossary of it. Certainly to any one who was not actually 

 dealing with the problems, the number and usage of the terms 

 met with in the different memoirs on the subject offered a 

 serious stumbling-block. This will be got over if the termin- 

 ology here proposed should be generally adopted. Various 

 bodies and their changes have been investigated, including 

 Mitochondria, Chondrioplasts, and a new set of structures 

 termed post-nuclear granules, and also their reactions to stains 

 and fixatives discussed. Finally, it is concluded that " it will 

 be seen that strong evidence is being collected against the view 

 that the Mitochondria take any part in the transmission of 

 hereditary characters." 



As the result of " Studies on the Physiological Significance 

 of Certain Precipitates from the Egg Secretions of Arbacea and 

 Asterias " (Jour. Exp. Zool. vol. xxvi. No. 3, August 191 8), 

 Woodward concludes that the secretion, which is of the nature 

 of a nitrogenous celloid, contains two distinct substances. The 

 first is a sperm agglutinin which activates and reversibly agglu- 

 tinates sperm of the same or allied species. The second is a 

 parthenogenetic agent destroyed by boiling capable of dealing 

 with an unsaturated fatty acid from the egg. " The Develop- 

 ment of Echinocardium cordatum : Part 2, The Development 

 of the Internal Organs " (Quart. Jour. Micro. Sci. vol. lxiii. 

 Part 2, August 191 8) by MacBride constitutes, together with 

 his previous paper on the same species, the first complete 

 account of the development of a Spatangoid. It is interesting 



