220 



SCIENCE. 



[N. S. Vol. XIX. No. 475. 



Msh of water about one inch from the 

 electrode). The body is turned so that 

 the long axis comes to lie approximately in 

 the direction of the current, the aboral end 

 is directed toward the anode, and the ani- 

 mal moves with more or less rapidity (de- 

 pending upon the strength of the current) 

 to the cathode. With a very weak current 

 the animal may simply orient itself without 

 movement towards the cathode. Still 

 weaker stimulation may simply cause slight 

 muscular contraction and movement of 

 cilia without orientation. Reversal of 

 current causes reversal in the orientation 

 of the animal and reversal in the direction 

 of its progression. The immediate cause of 

 the change in direction of the animal is a 

 reversal in the direction of the beat of the 

 ciliated paddle-plates. In general, these 

 may be said to beat more strongly in the 

 direction of the anode. But orientation is 

 brought about by more vigorous beating of 

 the plates in certain regions of the body — 

 possibly more strongly in the more direct 

 lines of current. Muscular action also aids 

 in orientation and in locomotion. Obser- 

 vations on the action of cilia and muscles 

 under the induced current were also made, 

 but are too incomplete for present notice. 



*Mouth Parts and Oviposition of Gall- 

 producing Insects: Mel. T. Cook, De 

 Pauw University. 



Gall-producing insects have two methods 

 of depositing eggs, i. e., on the surface of 

 the plant and within the tissues. In the 

 ease of the hymenopterous insects, the eggs 

 are placed within the tissues of the bud, 

 the incipient shoot or in the undeveloped 

 leaves of the bud. There is no indication 

 of chemical stimulus. The gall forms after 

 the hatching of the larva and is probably 

 due to the stimulus from the mouth parts 

 of the larva. The mouth parts are of two 

 forms, those for sucking and those for bit- 

 ing. The strength of the mandibles varies 



with the firmness; of the gall. The stimulus 

 is due to mechanical irritation. 



*The Bermuda Biological Station for Re- 

 search: E. L. Mark, Harvard University. 

 *A Theory of the Histogenesis, Constitu- 

 tion and Physiological State of Peri- 

 pheral Nerve: Poktek E. Saegbnt, Cam- 

 . bridge, Massachusetts. (Read by title.) 

 To be published in the Journal of Com- 

 parative Neurology and Psychology. 

 ■^The Two Chief Faunce of the Earth: 

 Alpheus S. Packard, Brown University. 

 (Read by title.) 



From the recent studies on the distribu- 

 tion of several groups of moths, I have been 

 led to review the recent work and views 

 of those who advocate the former connec- 

 tion between South America and Africa, 

 and the possible connection of the southern 

 land-masses with Antarctic land. There 

 seem to be two main centers of origin, i. e., 

 two chief zoological areas — that of the 

 northern and that of the southern con- 

 tinents. To the former Huxley's name, 

 Arctogffia, is -by general consent applied. 

 For the southern area Sclater's name, 

 Antarctogfea, may be employed. Indeed, 

 we had thought of this term before learn- 

 ing that the name had already been sug- 

 gested. Although Gadow extends the term 

 Notogsea so as to embrace the three south- 

 ern continents, yet it seems preferable to 

 confine it to its former limits. The Ant- 

 arctogsean area thus includes what are re- 

 garded by Blandford, Lydekker and others 

 as two separate realms, i. e., Neogsea (South 

 and Central America) and Notogsea (Aus- 

 tralasia, Polynesia and Austro-Malaysia), 

 while Africa south of the Sahara was re- 

 garded as a region or dependence of 

 ArctogEBa. The opinion, however, that the 

 form and distribution of the continents 

 were very different in past ages from 

 what they are now is gaining ground. 

 Thus northeastern America and western 



