154 



HITCHCOCK'S ANATOMY. 



tached to the cephalic cartilage. Annelids move by sub- 

 cutaneous muscles, stings, and bristles. The Rotatoria re- 

 volve by a retractile vibratile apparatus. Crustaceans have 

 usually two legs to each segment, and the Myriapods some- 

 times four. Some of these appendages are tactile, some for 

 oars, and some ambulatory. Spiders have four pairs of legs, 

 and insects three. 



287. Examples of Muscular Strength —There are some 

 remarkable examples of muscular strength among the lower 

 animals. A flea harnessed will draw from seventy to eighty 

 times its own weight, while a horse can not draw more than 

 six times his weight. The flea weighs less than a grain, and 

 will clear several feet at a leap. The common dorr bettle, 

 weighing but fifteen grains, has been known to heave a weight 

 placed upon him amounting to 4.769 grains, equal to nearly 

 320 times his own weight. 



288. Length of Time the Muscles can be Employed. 



— The length of time during which some muscles can be em- 

 ployed without rest is also very remarkable. Many birds will 

 fly uninterruptedly for hundreds of miles, and it is also said 

 that insects will remain suspended in the air a whole sum- 

 mer's day without alighting. 



289. Rate of Flight of Birds.— Some birds fly sixty 

 feet in a second ; but a race-horse scarcely ever exceeds forty 

 feet in the same time. A falcon of King Henry II. flew on 

 one day from Fontainbleau to Malta, a distance of about 

 1,000 miles. The rice-bird, which afterwards becomes the 

 reed-bird of Delaware Bay and the bobolink of New York, is 

 often found below Philadelphia with green rice in its crop. 

 The same thing is true of pigeons during the rice-growing 

 season. 



287. State the power of a flea compared with a horse. 28S. What is wonderful about 

 the length of time that some insects can use their muscles without weariness? 289. Witk 

 what speed can some birds fly? Give the iustance of King Henry's falcon. 



