GLASGOW SOCIETY OF FIELD NATURALISTS. 185 



PAPER READ. 

 Mr. W. D. Benson read a few notes on the " Fresh-water Hydra." 

 After givmg an outline of their discovery and the various 

 experiments made with them by Trembley in 1743, he proceeded to 

 show their place in Nature — their habits, and where found. 

 Remarking that while Hydra vlridis and Hydra vidgarls were 

 common he had never met with Hydra fusca in this district. These 

 Hydrae possess extraordinary power of resisting mutilation, and of 

 multiplying artificially when mechanically divided. No matter how 

 many pieces we cut one into, each and all will be developed into a 

 perfect hydra. Reproduction is effected sexually and asexually. In 

 the sexual mode of reproduction the spermatozoa are developed in 

 little conical elevations, while the ova are enclosed in sacs situated 

 near the base of the attached end. Usually there is only one sac 

 containing a single ovum, but occasionally there are two. When 

 mature the ovum is expelled, and is at the same time fecundated by 

 spermatozoa. The embryo is a minute free-swimming animal 

 possessed with cilia. The asexual mode is a process of reproduction 

 by gemmation, a new individual being gradually produced like a bud 

 from a plant. Mr. W. D. Benson then read from a number of notes 

 he had made when observing Hjdrae and their parasite "Trichodina 

 pedicidics" in his aquarium, where he had them constantly under 

 microscopic observation for some months. 



8th August, 1876. 



Mr. W. J. Milligan, Vice-President, in the chair. 



Mr. Thomas Boyle, 4 Montrose Street, was elected a member of 

 the Society. 



The Chairman stated that it was expected that the lists of the 

 Fauna and Flora of the West of Scotland would soon be out. It 

 was also stated that entrance to the Queen's Rooms, for the purpose 

 of putting in order the Botanical exhibition for the meeting of the 

 British Association, would be obtained on the 29 th inst. 



SPECIMENS EXHIBITED. 



By Mr. James Allan. — A cockchafer, Melolontha vidcjaris, from Dr. 

 Paxton, Sutton, Surrey. 



