Rotijera o/ Australia. 87 



typical or peculiar Rolotorian fauna for any continent, zone or 

 region." I submit that in view of the facts now stated in regard 

 to the genus Lacinularia and its mode of occurrence, this decision 

 is premature. There can be no doubt that man's activities are 

 efficient agencies for the distribution of rotifers, and may largely 

 account for the wide diffusion of species now observed, but, if 

 isolated occurrences of the five species described and recorded 

 solely from Australia should be discovered, it seems reasonable 

 to regard them as most probably due to those agencies. 



As above stated, the forms are conspicuous, and besides all 

 appear in enormous numbers at times. The free swimming 

 colonies fill the pools, it being impossible to dip an ounce of 

 water free from them. The method of development indicates 

 adaptation to the peculiar climatic conditions. The resting eggs, 

 having lain dormant throughout the summer in the dried mud 

 in hollows, on the fall of rain in early winter develop simul- 

 taneously with the eggs of other animal and vegetable organisms. 

 Generally, the plant forms are the first to mature, and thus a 

 supply of food is ready for the swarms of minute animals which 

 follow. The early part of the wet season is the time when in 

 a given pool a particular species often predominates • almost to 

 the exclusion of all others. This is specially noticeable in the 

 five species, L. elliptica, L. elongata, L. striolata, L. natans, and 

 L. reticulata. 



L. striolata practises a unique method of multiplication of 

 colonies, which strongly suggests a special adaptation to the 

 environment. The clusters are sedentary, being attached by a 

 peduncle to aquatic plants, and a single colony may consist of 

 thousands of individuals. The growth of the colonies in this 

 species is not due to successive generations of individuals taking 

 their places in the colonies alongside their parents. The method 

 is as follows: After the rain forms a pool the resting eggs of 

 the, previous season germinate, and give rise to free swimming 

 individuals, which come together and form small colonies. Im- 

 mediately in these colonies, the individual members of which are 

 all females, parthogenetic eggs appear, and hatching out in the 

 gelatinous nidus, the newborn rotifers swim away and combine 

 with similar forms from other colonies to form a new cluster; 

 thus a colony consists only of the animals which initiate it, and 

 the colonies become successively larger as the increase in number 

 goes on. This swarming process goes on until the food supply 



