56 POPULAR SCIENCE MONTHLY. 



eled out of the white layer and rests on a colored groundwork, 

 blue, pale salmon, etc. 



A very strange little fellow is RMzocMlus antipatharum. In 

 his youth he has a well-formed shell, hut as he grows older he 

 cements about it bits of coral, other shells, and anything which 

 he finds convenient, until the opening is entirely closed, and he 

 can communicate with the outer world only by means of his 

 siphon. 



One of the largest shells found on the coasts of the northern 

 and middle Atlantic States is Scycoiypus canaliculatus. It is 

 protected from injury by its coat of rough brown fur. The in- 

 habitant comes ashore to lay her eggs, which are a great curiosity. 

 There are hundreds of little leaflike sacs which contain the eggs, 

 all joined together, forming a long chain. 



^ons ago the shells had very different forms from those of 

 to-day, but we have left a few members of the group which ex- 

 isted in countless millions. The nautilus of the present time is 

 not a very distant relative of the ammonites, which we find so 

 marvelously preserved in the Silurian deposit, every line and pen- 

 ciling absolutely perfect. 



Note. I am greatly indebted to Prof. J. S. Kingsley, who was my teacher of biology at 

 Tufts College, for his assistance to me when I was studying the shells, and for material in 

 this sketch taken from his article on Mollusca in the Standard Natural History. 



THE EMPLOYMENT OF THE MOTOR ACTIVITIES IN 



TEACHING. 



By Prof. EDWAKD E. SHAW, Ph. D., 



DEAN OF THE FACULTY OF PEDAGOGY, NEW YORK UNIVERSITY. 



THE recent development of our knowledge of the nervous 

 mechanism in its relation to the processes of education leads 

 us to appreciate the great worth of the ideas advanced by two 

 educators of the last century, Basedow and Heusinger, and also 

 to see quite clearly the great advantage which will result in the 

 work of the school from the applications of the truths set forth 

 by them. 



When Basedow said that children were fond of noise and 

 movement, that they hated to sit still for a long time, that a con- 

 tinued strain of attention and learning by rote were distasteful to 

 them, and that only by force could they be trained to such vexa- 

 tious employments, he apprehended a truth upon which the re- 

 searches of recent years have given us more specific knowledge ; 

 and his warning that through the disregard of this principle not 

 only the health of the pupils is weakened, but also their intellect 



