THE NATURAL HISTORY EXCURSION 147 



snail with transparent shell is found. Bring two specimens 

 for the aquarium, taking care not to break the shells. 



9. If the sun shines, Volvox may be found abundantly in 

 the same pond by sweeping with a muslin net. Collect 

 specimens, and float them into a wide-mouthed bottle. 



Where animals, even animals of low grade, are captured, 

 the greatest care must be taken to- avoid cruelty. The 

 specimens collected for examination should either be 

 speedily returned uninjured to their native haunts, or, if 

 required for study, killed expeditiously by immersion in 

 a preservative fluid, such as alcohol, or a 4 per cent, 

 solution of formalin. On no account should a number of 

 different live animals be allowed to torment one another 

 by being carried in the same vessel. 



It is good to follow up the field -excursion by a meeting 

 for examination of results. Things may then be studied 

 which before were only glanced at ; and things of great 

 interest will very likely be brought to light which escaped 

 notice when they were captured. The chief difficulty to be 

 faced is that such a crowd of objects will often be brought 

 home that there is not time to examine all carefully. When 

 this happens, my advice would be : Avoid distraction, no 

 matter how many curious objects are passed over. 



XXIX. THE ORGAN-GRINDER'S MONKEY. 



We call this a monkey, because he has a long tail ; the 

 man-like apes (orang, chimpanzee, gorilla and gibbons) 

 have no tails at all, and the baboons, which live much on 

 the ground, either have no tails or much shorter tails than 

 this. His tail curls downwards at the tip ; this tells us 

 that it can be used in grasping. 



The organ-grinder's monkey comes from South America ; 

 one could see that by merely looking at his face ; for 

 the nostrils are separated from one another by about 



