Septejibee 13, 1895.] 



SCIENCE. 



343 



ments for the wind theory, as generally stated, 

 are first, the general accordance of prevailing 

 winds and associated currents ; each ocean hav- 

 ing its wind eddy only less marked than its cur- 

 rent eddy. Second, the periodic variation of 

 the currents in regions of monsoon winds ; the 

 type example of this kind being in the Indian 

 Ocean, where, as even Dampier noted two hun- 

 dred years ago, the currents shift about a month 

 after the winds. Third, the irregular move- 

 ments of the surface waters under storm winds, 

 which suffice in a day or two to deflect or even 

 to reverse the surface layers of so strong a cur- 

 rent as the Gulf Stream off" Hatteras. To these 

 facts may be added the hardly less significant 

 behavior of the equatorial counter currents, 

 which increase in area and strength on that 

 side of the equator to which the trade wind 

 from the other hemisphere crosses over as a de- 

 flected, monsoon-like wind; the monsoon cur- 

 rents of the Indian Ocean being only special 

 cases of this general rule. The greater velocity 

 of the North Atlantic drift (' North connecting 

 current' in the objectional terminology of the 

 school atlases) in winter than in summer may 

 also be mentioned as a fact best explained by 

 the wind theory. There is nothing about the 

 Gulf Stream so peculiar as to exempt it from 

 the general control exercised by the winds over 

 the waters. W. M. Davis. 



Haevaed TJniveesity. 



corrections. 



Editor of Science : The fate of my review 

 of Beddard's Zoogeography furnishes another il- 

 lustration of the dangers which an author is sub- 

 ject to in his path to publication. In the proof (of 

 which I have a duplicate at hand), Nearetic 

 and Ostolwmus occur all right, but in the pub- 

 lished article (altered after it passed through my 

 hands) Osteolxmus is substituted for Ostolsemus 

 and Osteoloemus for Osteolsemus and consequently 

 there is no apparent point to the criticism made 

 and no reason for the analogue educed. ' Upi- 

 form' on p. 273 (left column) should have 

 been pupiform, and ' even ' on p. 273 (right 

 column) just before ' the same Hyracodon ' 

 should, of course, have been event. The ]) of 

 .pupiform and t of event were dropped after 



transmission of the proof ; ' molacologist ' should 

 have been corrected to molacologist. 



I may add that Mr. Beddard spells the title 

 of his volume Zoogeography (without 6) as I 

 had written and corrected. 



The reviewer of Beddard's work in ' Nature ' 

 (July 25, p. 289) is "at a loss to understand" 

 ' ' by what confusion of ideas the name Hyracodon, 

 (which belongs to an extinct genus of rhinoce- 

 ros-like animals) is made to do duty for Didel- 

 phys." Hyracodon of Tomes, as noted in the re- 

 view in Science (p. 273) was published in 1863 

 and in the Proc. Zool. Soc. London (p. 50) and 

 has remained unexplained to the present day. 

 I have long been inclined to believe that it was 

 based on a young Didelphys, although the mea- 

 gre description does not apply to any stage I 

 have seen (and I have seen many). I was sur- 

 prised that it was not noticed in Mr. Thomas' 

 excellent work on Marsupials. It seems, in- 

 deed, to have fallen quite flat, but was noticed 

 by MvuTay in his geographical distribution of 

 Mammals, and I presume that it is from Murray 

 that Mr. Beddard has received the generic name. 

 The homonymy of the names of Leidy and 

 Tomes was, of course, a mere coincidence. The 

 type of Tomes' genus {Hyracodon fidiginosus) was 

 from 'Ecuador; collected by Mr. Eraser.' If it 

 has not been lost, perhaps Mr. Thomas may 

 find it and tell us what it is. 



We may, perhaps, derive some comfort from 

 the fact that the printers of your famous con- 

 temporary ' Nature ' are by no means exempt 

 from errors like those I now correct. Eour 

 lines before the reference to Hyracodon just 

 cited, we find a reference to the ' Siberian hip- 

 popotamus ; ' the original copy of the review 

 undoubtedly had Liherian. Theo. Gill. 



Washington, Aug. 31, 1895. 



[In the issue of Science for August 30, 

 smaller type was for the first time used in part 

 of the number. As is apt to happen in such 

 cases there was a delay in the arrival of the 

 type and the proof was late. Dr. Gill's correc- 

 tions were sent to the printer, but the corrected 

 proof was not seen by the editor. The errors 

 are however such (presumably due to resetting 

 part of the article) that it is better to offer 

 apologies rather then excuses. J. McK. C] 



