Ttfareh, 1907.] THE VICTORIAN NATURALIST. 223 



Naturally, the larger forms readily discernible by the 

 naked eye received most attention ; and, amongst these, 

 examples of the beetle tribe were found, which included 

 Dytiscus, Hydrophilus, both larval forms and the pet' 

 feet insects, and of course the family Gyrinidae perform- 

 ing their evolutions on the surface. Larval forms of the 

 dragon flies, caddis flies, dragging about their ingeniously- 

 made cases, mosquitoes, and many others were all pointed 

 out. Unpromising as the pools looked, specimens of 

 Polyzo'a rewarded the searchers, and opportunity was 

 taken to point out how the resting eggs of this and 

 ■others forms might lie dormant in the dust and retain 

 their vitality even in the extreme state of dessication im- 

 posed by our fierce summer heats, and allusion was made 

 to the rapidity with which the pools became stocked with 

 life when the autumnal rains filled the hollows with 

 ^vater. One pool was thought from its greenness to con- 

 tain Volvox, but closer examination showed that the 

 organism was a unicellular plant. Opportunity was 

 "taken to show what interesting problems, as to the dividing 

 line between animals and plants were raised by such forms 

 as Volvox. 



Opportunity was taken, also, to show that, besides a 

 scientific side, there was also an economic one, hydatids 

 and sheep fluke being matters on which a correct view of 

 their cause could be obtained by a knowledge of the pond 

 life organisms which harboured them. 



A second trip was made after lunch, and the pools 

 visited were all of the same character. The haphazard 

 way in which the objects turn up in such circumstances 

 necessarily made the work done of a disconnected charac- 

 ter ; and, further, many objects, as was, pointed out, re- 

 quired careful examination to determine, but the work 

 done would be of use to those previously unacquainted 

 with the subject who might apply themselves to it. 



AUSTRALIA'S MAMMALS AND THEIR PLACES 

 OF ORIGIN. 



By T. S. Hall, Lecturer and Demonstrator in Biology, 

 Melbourne University. ' 



The scrappy chapters on animal and plant distribution 

 at the end of geographies are usually bare catalogues. 

 The whole philosophy of the thing is ignored. We learn 

 that rhinoceroses are found in Africa, sloths in South 



