haps they all do more or less to help 

 along. But there are three ways left 

 that I think of. I think I shall have to 

 help you out with two of them. The 

 other I'll let you puzzle over. I neve^ 

 saw it named in the books ; and you 

 must watch for it yourselves." 



"There are clams that throw out a 

 long arm, attach it to something station- 

 ary and then, by contracting it, dra^ 

 themselves along. Then there are other 

 bivalves that open wide their shells, then 

 by suddenly snapping them together 

 again eject the water, and so drive them- 

 selves along by repulsion. 



"I dare say there are other ways that 

 I don't think of just now ; but these, with 



the one that is a secret, will do for the 

 present. 



"Now, Tommy, my boy, there would 

 be more sameness in the world if we had 

 only your three ways of getting on in 

 it. But, never mind, you were good to 

 be eager to answer right off." 



"Aren't you going to count the para- 

 sites?" asked the big sister. 



"No, I think not. They are only after 

 free board and lodging. I don't think 

 they care anything about the ride thrown 

 in." 



"Oh, please, Uncle Jarvis, tell us the 

 other one !" they all cried with one breath. 



"No; it is the most curious of all, and 

 I am going to make you look for it." 



PART II. 



"O, Uncle Jarvis," began the children 

 one day, "we can't wait till holiday out- 

 ings begin. Won't you tell us now abor 

 that funniest way of moving about?" 



"Well, let me think," said the old man. 

 But we knew it would come out after a 

 while. 



"I certainly must not forget the spider- 

 monkey, that with hands, feet and tail 

 swings himself along from branch to 

 branch in the thick forests of the tropics. 

 We may class him as the swinging type. 

 Then there is the skating type which I 

 quite forgot the other night, often as we 

 have watched him. That is the water- 

 spider. How beautifully he glides over 

 the still pool, without wetting his legs ! 

 Why doesn't he sink? Well, his body 

 is very light, and his feet are protected 

 against water soaking. A big, fat spider 

 couldn't skate." 



"You didn't tell us how the snail 

 moves," said the oldest boy. "The dirty, 

 slimy things ; I dislike them. They have 

 no legs to creep with, and they don't 

 snake themselves along. I watched one 

 today, and I can't imagine what moved 

 it." 



"If you had looked where the snail 

 touched the ground, instead of at his 

 back," said the old man, with a mischiev- 

 ous twinkle, "you would have been a bet- 

 ter naturalists. Besides, naturalists don't 

 dislike their subjects. The next time you 

 see a dear little snail — the shinier the bet- 

 ter — put a piece of glass ahead of him, 

 and when he gets onto it, turn it over 



and watch the movements of the spiral 

 rings on his under side. They will look 

 like threads of a screw, alternately 

 opaque and transparent, and they wind 

 around incessantly toward his head, as if 

 they were screwing him forward. Dirty, 

 indeed; nothing is dirty but vermin." 



"Now, how could I have forgotten," 

 Uncle Jarvis continued, "the climbing 

 caterpillar? Some of the larvae seem to 

 be very restless. We see them in mid- 

 summer swinging from the branches of 

 the trees till they reach the ground. There 

 is nothing there worth staying for, and 

 they soon want to go back. Now comes 

 a style of locomotion unlike anything we 

 have talked about." 



"Is it as queer as that one you are go- 

 ing to tell us about?" asked some of the 

 listeners, mischievously. 



"Don't interrupt," returned the narra- 

 tor, trying to frown. 



"Well, this caterpillar catches hold of 

 the line by which he came down, drags 

 on it with his mouth and holds the slack 

 between his forefeet. Then he reaches 

 up, grabs another length with his mnr' 1 

 and holds it like the first. And so on till 

 he may be seen high up, swaying abon( 

 with a fuzzy bundle of his cable in front 

 of him. 



"When a bov I often watched this fel- 

 low climbing his rigging, and tired my- 

 self thinking how tired he must get. Just 

 think ! take a branch say fifteen feet from 

 the ground, and say that our climber 

 takes a quarter of an inch at each pull. 



139 



