632 



SCIENCE. 



[N. S. Vol. XXI. No. 538. 



spotted moray. Perhaps the most interesting 

 things which came from the surface of the 

 banks were a number of calcareous spheres 

 three or four inches in diameter. They were 

 composed of thin concentric layers and were 

 apparently of organic origin. Further than 

 this no explanation of their origin was forth- 

 coming. 



Alfred Russel Wallace has pointed out how 

 typical the Bermudan terrestrial fauna is of 

 an oceanic island. Only three indigenous 

 vertebrates are present otherwise than birds. 

 It is significant that the only mammal is 

 winged, a bat. He expresses surprise at the 

 small number of insects described. Since the 

 publication of his book the list has been 

 swelled to over three hundred. That a con- 

 siderable proportion are not indigenous is evi- 

 dent from the fact that twenty species were 

 found en route for Bermuda on one ship sail- 

 ing from New York. The gulf stream flow- 

 ing within one hundred miles to the west of 

 Bermuda, the drift of the surface water from 

 the south and west, and the West India hurri- 

 canes were no doubt the important agents in 

 bringing animal life from the North Amer- 

 ican continent. J. E. Kirkwood, 



Corresponding Secretary. 



THE ELISHA MITCHELL SCIENTIFIC SOCIETY OF 

 THE UNIVERSITY OF NORTH CAROLINA. 



The 159th meeting of the society was held 

 in the chemical lecture room, Tuesday, 7:30 

 P.M., March 14, 1905. The following papers 

 were presented: 



Professor A. S. Wheeler: 'Normal Paper.' 



Professor W. C. Coker: 'The Mutation Theory.' 



Professor J. E. Mills: 'Chemical Affinity: A 

 Method for Distinguishing Chemical Energy from 

 Simultaneous Physical Energy Changes.' 



Alvin S. Wheeler, 



DISCUSSION AND CORRESPONDENCE. 



NATURAL MOUNDS. 



In Dr. Brauner's interesting article on 

 ' Natural Mounds ' in Science for March 31, 

 he mentions the fact, in connection with the 

 distribution of these mounds in the Mississippi 

 Valley, that they follow up the valley of the 

 Arkansas and of the Neosho rivers across 



Indian Territory into southeastern Kansas. 

 These mounds are exceedingly abundant in 

 southwest Missouri also. They are a char- 

 acteristic feature of the landscape in Lawrence 

 County, Mo. (second tier of counties from 

 Kansas and from Arkansas), where the writer 

 lived for many years. They are abundant 

 both in the timber and on the prairies, but are 

 more noticeable on the prairies because of the 

 fact that on them the prairie grasses give place 

 to taller forms of vegetation. Before the 

 lands were put in cultivation these mounds 

 were from one to three feet high, and usually 

 twenty to thirty feet in diameter. On newly 

 reclaimed land crops grow much more lux- 

 uriantly on the mounds than elsewhere. Com 

 is usually the first crop planted on new lands 

 in that section, and it is usual for corn on 

 mounds to grow nearly twice as tall as on sur- 

 roimding areas the first year. This difference 

 in growth gradually disappears as cultivation 

 continues. 



These mounds have probably originated 

 from different causes in different regions. In 

 southwest Missouri their origin is probably 

 due to the following cause : The soil of the 

 region has been formed from the decay of the 

 great sub-carboniferous limestones. Where 

 these strata are exposed in cliffs there may 

 occasionally be found concretions of flint sev- 

 eral feet in diameter. The flint is broken into 

 rather small fragments, which fall apart more 

 or less when the surrounding limestone dis- 

 integrates into soil. The flint resists dis- 

 integration far greater than the limestone. 

 These masses of flint fragments later become 

 prominent as mounds by the more rapid de- 

 nudation of the surrounding soil containing 

 comparatively little flint. This theory is 

 strengthened by the fact that the material 

 forming the mounds to a depth of several feet 

 consists very largely of small flint stones. 



W. J. Spillman. 



U. S. Department of Agbiculture. 



SPECIAL ARTICLES. 



an alternative INTERPRETATION OF THE ORIGIN 

 OF GYNANDROMORPHOUS INSECTS. 



The occasional occurrence in the groups of 

 ants, bees, wasps and butterflies of individuals 



