THE VICTORIAN NATURALIST. 35 



rise. Whether in horizontal swing or in rising and sinking to 

 and from the vertical, the motion was always spasmodic and 

 jerky, and is, I think, due to a tremendous tensile strain on 

 temporary organs of attachment, which, probably because of a 

 little flocculent matter, which more often than not adhered to 

 the apices, I have not been able to make out. 



This is explained if the most recent acceptable description of 

 the character of the cell wall is correct. The wall consists of an 

 inner coat of cellulose, in which innumerable pores give egress to 

 protrusions of the cell protoplasm ; these form a mucilaginous 

 outer coat to the Desmid, and it is supposed that by means of 

 the protruded protoplasmic threads the plant can attach itself to 

 foreign objects. In a glass tube, which at the moment of 

 writing I have under observation, there are scores of the crescent- 

 shaped Closterium referred to above. These have within forty- 

 eight hours travelled from one side of the one-inch tube to 

 the other, and are now motionless near to the glass side, 

 all attached by one apex, in an almost erect position, and 

 with their edges turned to the light, which attracts them through 

 a slit in a cylinder covering the tube. Several Pleurotaeniums 

 cling meanwhile to the side of the glass tube, as though for them 

 the light was a more powerful attraction, most of the Closteriums 

 having stopped a little short, attached to debris on the floor of the 

 tube. 



(To be continued.) 



FIGHTS BETWEEN TWO SPECIES OF ANTS. 

 By J. A. Hill. 



{Read before Field Naturalists' Club of Victoria, 8th May, 1905.) 

 During my long residence at Kewell, in the Wimmera District, I 

 have frequently had the opportunity of witnessing some of the 

 fierce battles which take place between two species of ants, and 

 it has been suggested to me that a few notes on the subject would 

 be of interest, and probably induce some of our country members 

 to supplement them. 



One of the commonest species of ants in this district is that 

 known locally as the Soldier Ant, Formica purpurea, a species 

 about ^8-inch long, which constructs large subterranean nests, 

 often measuring on the surface from 12 to 15 feet in diameter. 

 These nests contain thousands of inhabitants, and woe betide the 

 animal that may unconsciously take its stand upon or near their 

 abode. I have frequently seen small snakes, slow worms 

 (Ti/phlops), and large insects fall a prey to their voracious habits. 

 That these great colonies should be entirely annihilated by a 

 small black species, only about one-third their size, seems almost 

 incredible, but such is the case. 



