716 KEPORT— 1888. 



of their expulsion, no part of the inner protoplasm is exposed directly to the water ; 

 and we have a mechanism which expels regidarly the plasmatic juice or cell-sap 

 when over-diluted and over-abundant, and which prevents the destruction of the 

 protoplasm by bursting and diffluence. This is the mechanism of the contractile 

 vacuole, which is thus a physiological necessity to the naked cell living in water 

 like the kidney is to the multicellular animal organism. 



I will add one unpublished observation to the well-known facts here brought 

 together. Two sporanges of Saprolegnia opened at an early stage of the partial 

 segregation of the protoplasm into masses. Part of the protoplasm in each slowly 

 escaped and aggregated into rounded masses. The first discharged masses under- 

 went the usual pathological changes and diffluence; the later masses (from both 

 sporangia) had already acquired the power of forming contractile vacuoles pos- 

 sessed by the zoospores ; the numerous small vacuoles appeared and contracted 

 regularly, lines of separation formed and deepened, and the masses divided into 

 zoospores which separated and swarmed, just like the protoplasm which remained 

 in the sporange, though more slowly. This observation seems to afford a crucial 

 t€st of the truth of the thesis that the contractile vacuole has the function of pre- 

 venting excessive vacuolation and diffluence of naked cells in water. 



The following is a brief summary of the points on which the above thesis 

 rests : — 



1. All naked protoplasmic bodies living in fresh water have at least one con- 

 tractile vacuole. 



2. The possession of this is quite independent of the systematic position of the 

 organism. 



3. The vacuole loses its contractility on the formation of a strong cell-wall or 

 cyst and may even disappear. 



4. It is absent from Gregarinida and Opalinia, and the Madiolaria which 

 inhabit saline liquids. 



5. When, owing to morbid conditions, the efficiency of the contractile vacuole 

 is impaired, excessive vacuolation and diffluence ensue. 



6. Conversely, as soon as contractile vacuoles appear the tendency to excessive 

 vacuolation and diffluence is arrested. 



It may be suggested that the perforations of the nephridial cells in Vermes and 

 embryonic moUusks, and of the epiblastic gland-cells of Vermes and Arthropods, 

 are due to the persistence of the contractile vacuole, the opening of which has 

 become permanent, while its contractility has been superseded in the kidneys at 

 least by other arrangements. Even the goblet-cells of mucous epithelia may 

 possibly be traced to this origin. 



9. On the Contrivances for the Seed Protection and Dislrihution, in 

 Blumenbachia Hieronymi, Urban. By W. Gardiner. 



Zoological Department, 



1. On Locusts in Cyprus. By S. Brown. 



The author gave a brief description of the habits of the common Cyprus locusts 

 {Sf.aia-onofus crociati(s) and of the system which has been successfully employed 

 for their destruction in Cyprus. These insects have from time immemorial been 

 the scourge of the island, and as, under Turkish rule, little was done to keep them 

 down, their ravages formed probably the chief agency in reducing what was once a 

 fertile and flourishing island to a condition of comparative desolation. Successful 

 efforts were, however, made by the Turkish Government from 1862 to 1870 for the 

 destruction of the locusts, and in the latter year the island was so far rid of them 

 that for some time no injury was sustained by the crops. But the Government 



