28 Transactions of iJie Society. 



Planorhis coi^neus and Valcata piscinalis under observation for the 

 early stages of development. I have a large number of eggs 

 embedded for future cutting, after using pereny and acetic sub- 

 limate as fixing reagents. Towards the end of an egg-laying period 

 in L. stagnalis I frequently found some of the egg-capsules with 

 numerous eggs, up to fifteen in number, instead of the normal 

 single egg. I also managed to hatch out several cases of two 

 ■embryos from one capsule. A curious incident occurred with the 

 aquarium in which there were specimens of P. corneus, and the 

 only specimen of Pahidina rivipara I have been able to find. One 

 night five of these snails, including the Paludina, were dragged 

 out of the aquarium and devoured by a rat. The aquarium is now 

 removed to a safer place for protection from further invasion. 



Eeport on Biological Activities in Euhleben. 

 Fkom Michael S. Pease, B.A. Cantab., dated August 14, 1917. 



The first outward sign of biological activity in Euhleben 

 appeared in the spring of 1915, when I)r. A. E. Lechmere started a 

 series of lectures on Elementary Biology. These were held in a 

 disused betting-booth, and attended by half-a-dozen enthusiasts. 

 In the summer, one of the grand-stands was set aside for lectures, 

 and Dr. Lechmere continued his course on the Protozoa, while I 

 contributed a course of twenty lectures on Heredity. At Christmas, 

 1915, the loft of Barracks 6 became available for educational 

 purposes, and tlie first weeks of the new year saw the conversion 

 of a corner of a somewhat dilapidated hay-loft into a biological 

 laboratory. By the end of January the accommodation for eight 

 microscopes was provided. The necessary glass-ware and reagents 

 were got in from Messrs. Leitz, and practical botany, of a neces- 

 sarily elementary character, was started with twenty-one students. 



In the following terms regular lecture courses in botany were 

 given by myself, and the corresponding practical work was of a 

 more thorough and extensive nature. The ground covered has been 

 as follows : — 



Bryophytes and Pteridophytes (Summer, 1916). 

 Gymnosperms (Autumn, 1916). 

 Algai (Lent, 1917). 

 Angiosperms (Summer, 1917). 



Spirit material was kindly presented to us by Prof. A, C. Seward, 

 Dr. Darbishire, and Prof. Tubeuf. 



We are indebted to Prof. Engler for a weekly supply of flowers 

 from the Kgl. Botanischer Garten, Dahlem, for the systematic 

 course. A pond within the race-course has been our source of 

 fresh material for Algae and Protozoa. 



The equipment of the laboratory has been continuously im- 



