958 



SGIENGE, 



[N. S. Vol. V. No. 129. 



8. In conclusion I should like to direct atten- 

 tion to the final statement of Mr. Sclater. 

 Having made the (incorrect) supposition that 

 the late-Tertiary group of the eared seals has 

 been checked in its northward advance in the 

 Atlantic by a connection of South America and 

 Africa, he says that " all these facts, with the one 

 exception of the supposed Atlantic barrier, would 

 tend in favor of the now generally accepted doc- 

 trine that the principal masses of land and water 

 are not of modern origin, but have existed 

 mainly in their' present shapes throughout all 

 ages." No less than three errors are contained 

 in this single sentence, namely : 1. It is impos- 

 sible to derive from the distribution of a group 

 of Tertiary animals any conclusions as to the 

 shapes of the principal continental masses 

 throughout all ages. 2. This statement would 

 hold for the Tertiary time only if we consider 

 that the connection of South America and 

 Africa, which is supposed by Mr. Sclater, is no 

 important feature. Mr. Sclater admits that this 

 Atlantic barrier forms an exception to the rule ; 

 but, I should say, such an exception throws the 

 whole rule aside. 3. It may be that Mr. Sclater 

 himself has accepted the ' doctrine ' of the per- 

 sistency of the continents, but I protest most 

 vigorously against calling such a ' doctrine ' 

 generally accepted. A dogma (and this would 

 be the proper name for it) that has been contra- 

 dicted by students in zoogeography, such as 

 Baur, Beddard, Neumayr, v. Ihering and 

 others (and I should add, which is rejected by 

 almost all geologists) cannot be regarded as 

 ' generally accepted. ' 



The distribution of the Seals and Sirenians, 

 it is true, has never been investigated from a 

 scientific standpoint, but there are only a few 

 distributional features which seem to be anoma- 

 lous at first sight (Sirenia, Otariidse), and even 

 these may be explained readily. The Sirenia 

 point to conditions existing in the beginning of 

 the Tertiary period, and it is well known that 

 this group existed in the Eocene epoch. The 

 distribution of the Otariidse is analogous to what 

 has been called (improperly) ' bipolar ' distribu- 

 tion. They represent the somewhat rare case 

 of an Antarctic group of littoral animals which 

 has crossed the tropics along the western coast 

 of America and reached the northern Pacific. 



As to the latter fact I refer to a special paper 

 published by me recently, which is especially 

 devoted to this peculiarity of distribution.* 

 Arnold E. Oktmann. 

 Peincbtost Univeesity, Jtme, 1897. 



THE potter's wheel IN AMERICA. 



My neglect to mention the Kdbal, pointed out 

 in Mr. Mercer's letter (Science, p. 919), was not 

 an oversight, but for two reasons : First, as he 

 mentions, because the word with that meaning 

 does hot occur in the Maya dictionaries of the 

 sixteenth century; and secondly, because the 

 Kabul is not a potter's wheel in its results or in 

 a technical sense. 



This is shown in Mr. Mercer's own work, 

 ' Hill Caves of Yucatan,' p. 77, where he quotes 

 Captain Maler as saying that he ' had found no 

 trace of the potter's wheel in the old specimens 

 of pottery,' anywhere in Yucatan. Mr. Mercer 

 brought no potsherds from ancient deposits to 

 contradict this; and according to his own words 

 the Kabal, as used to-day, does not give ' the 

 regularity of outline ' which is the artistic aim 

 of the potter's wheel. (P. 164, note.) 



D. G. Beinton. 



SCIENTIFIC LITER A TUBE. 

 The Cambridge Natural History. Edited by S. 

 F. Harmer, M.A., and A. E. Shipley, 

 M.A. Vol. II., Flatworms, etc. Macmillan 

 & Co. 1896. 8vo. Pp. xii+560, 257 figs. 

 Volume II. of the Cambridge Natural His- 

 tory, the third of the series to make its appear- 

 ance, deals with those classes which are usually 

 grouped together as Worms or Vermes, and 

 Polyzoa. The different classes are treated by 

 specialists whose names are familiar in connec- 

 tion with the subjects assigned to them. The 

 work is shared by seven authors, as follows : 

 Platyhelminthes and Mesozoa, by F.W. Gamble, 

 pp. 1-96, Figs. 1-47 ; Nemertinea, by Lilian 

 Sheldon, pp. 97-120, Figs. 48-61 ; Nemathel- 

 minthes and Chsetognatha, by Arthur E. Ship- 

 ley, pp. 121-194, Figs. 62-105 ; Eotifera, Gas- 

 trotricha and Kinorhyncha, by Marcus Hartog, 

 pp. 195-238, Figs. 106-120; Archiannelida, 

 Polychfeta and Myzostomaria, by W. Blaxland 

 Benham, pp. 239-344, Figs. 121-186; Oligo- 

 * Zool. Jahrb. Syst., Vol. 9, 1896, pp. 571-595. 



