470 SUMMARY OF CURRENT RESEARCHES RELATING TO 



hand, the absence of certain species which are generally found living in 

 sheltered conditions where muddy beaches and Zostera beds occur, where 



the salinity is affected by the entrance of streams and the temperature 

 shows great fluctuations. A few of the characteristic features of the 

 shore fauna are : 1. The abundant representation of twelve species of 

 calcareous sponges. 2. The variety and small size of many sponges. 

 3. The absence between tide-marks of certain sponges found in that 

 zone on the mainland. 4. The abundance of anemones and the presence 

 of such forms as Sagartia venusta, Oorynactis viridis, Depastrum cyathi- 

 forme, HalkJi/stiis auricula, Lucernaria campanulata, and Oaryophyllia 

 smithii 5. The presence of large numbers of Strongylocentrotiis Uvidus 

 and Aster ina gibbosa, which are characteristic of exposed situations. 

 6. The large numbers of the Molluscs Hermsea dendriditica and Elysia 

 viridis, correlated with the abundance of their food-plant Codium tomen- 

 tasum, and the absence of Molluscs like GibbuJa magus, Acera bullata, 

 Mactra subtruncata, which thrive in a more sheltered habitat. And (7) 

 the absence of the Mollusc Trochocochlea linen, which occurs not far off. 

 The Clare Island littoral and sub-littoral fauna is compared with that in 

 some other similar areas. 



Present-day de Novo Origin of Living Organisms.* — H. Charlton 

 Bastian refers to the incredulity expressed in regard to his demonstra- 

 tions of " archebiosis." It has been supposed that the organisms that 

 appear on the slides have not come from the sterilized tubes, but from 

 a dirty pipette or slide. He points out that this objection can be dis- 

 posed of. It has also been suggested that the supposed living organisms 

 are either simulacra or dead organisms surviving after the sterilization. 

 This objection can also be answered. Moreover, tyrosine comes to the 

 veteran observer's aid, for a small quantity of a very dilute solution 

 causes the living organisms that may be present to grow and multiply 

 freely. " Before the tyrosine the organisms were mostly very small and 

 not too numerous, having often to be very carefully searched out ; while 

 after the influence of the tyrosine there were no longer any difficulties 

 of this kind, or indeed any room for still maintaining a sceptical attitude 

 on the ground that what are to be found in my tubes are either dead 

 organisms or mere simulacra : the unmistakable growth and multiplica- 

 tion of the organisms negatives all such suppositions." " Mere simulacra 

 or dead organisms may be not altogether absent ; but with the help of 

 the tyrosine it has been positively shown that the tubes contain crowds 

 of living organisms of different kinds." 



Hormone Theory of Transmission of Modifications.! — J. T. 

 Cunningham argues in support of the theory that stimuli involved in 

 the use of an organ caused hypertrophy in the part affected, and that 

 in the course of generations the tendency to this hypertrophy was trans- 

 mitted to the gametes. The hormone theory explains how such trans- 

 mission may be effected. The hypertrophied part gives off chemical 



* Proc. R Soc. Med., June 1915, pp. 1-12 (8 figs.). 



t Rep. British Assoc. Australian Meeting, 1915, pp. 419-20. 



