790 



SCIENCE. 



[N. S. Vol. XXV. No. 846 



Edwaed ICasnee: ' Isogonal and dynamical 

 trajectories.' 



P. L. Satjrel : ' On the distance from a point to 

 a surface.' 



T. E. McKiNNEY : ' On concylic quantics.' 



T. E. McKiNNET: 'On continued fractions rep- 

 resenting quadratic irrationalities.' 



G. A. Mtt.t.kr: ' Groups generated by n operators 

 each of which is the product of the n — 1 remain- 

 ing ones.' F. N. Cole, 



Secretary 



THE AMERICAN CHEMICAL SOCIETY. NORTH- 

 EASTERN SECTION 



A Correction. — ^In the report of tlie pro- 

 ceedings of tlie seventy-fifth regular meeting 

 of this section (this journal, p. 669), through 

 a mistake of the undersigned, the following 

 statement appeared : " For three semesters, the 

 speaker was Wohler's assistant and took part 

 in the researches on aluminium, silicon, boron, 

 etc." * * * Dr. Eemsen was not Wohler's as- 

 sistant and did not take part in the researches 

 on these elements, but did later make them 

 under Wohler's personal direction, by methods 

 which had already been worked out. The 

 speaker left Gottingen in 18Y0 and became 

 assistant to Fittig at Tiibingen. With a view 

 to correcting the false impression given by, 

 the above-mentioned report, these few lines 

 are put forth with the hope that they may 

 fall under the eyes of most of the readers of 

 the original report. 



Frank H. Thorp, 



Secretary 



DISCUSSION AND CmtRESPONDENCE 

 THE FIRST REVISER OF SPECIES 



I HAVE followed with much interest the re- 

 cent discussion in Science by Messrs. Stiles, 

 Stone, Jordan and Allen on the proposed new 

 rules in zoological nomenclature. The sub- 

 ject is one of especial concern to me at the 

 present time as involving the propriety of 

 numerous generic names in a work now pub- 

 lishing. I wholly agree with Dr. Allen in his 

 views regarding elimination, and concur quite 

 with his statement that elimination is prac- 

 tically the only rule in use by systematists, 

 at least so far as that especial group of in- 



sects with which I am best acquainted is con- 

 cerned. I believe that, upon the whole, it is 

 the safest and most expedient rule, and one 

 which meets the approbation of most taxono- 

 mists. Next to this I would accept the rule 

 of the ' first species,' one that has often been 

 used by entomologists, especially where there 

 has been no doubt as to the meaning of the 

 original describers. 



But the first species rule would be unjust 

 when applied to certain writers. It is well 

 known that Meigen, the 'father of dipter- 

 ology' did not consider the first species aa 

 the most typical of his genera, but rather, 

 with the last species, as the most aberrant, 

 and these were the ones he usually figured. 

 Wiedemann, a very prolific describer of exotic 

 diptera on the other hand, arranged his species 

 in his genera usually in the order of their size, 

 and the first here would not in the least repre- 

 sent his most typical species. 



As to the rule of the 'first reviser,' when 

 applied to work done in the past, I consider 

 it vicious; so utterly unjust and revolution- 

 ary that it is to be hoped it will be stifled 

 in its birth. I, for one, shall never recognize 

 it. Its chief use would be to give unlimited 

 license to the library naturalist, now that 

 ' new genera ' are not so common as they were. 

 I will mention a single instance of the effect 

 it would have in a case that has recently 

 been brought to my attention. There is per- 

 haps no genus of files better known, save 

 Musca, than the genus Syrphus. Fabricius 

 named the genus in 1Y75, giving a list of 

 numerous species belonging to it, a composite 

 genus of course, as aU of Fabricius's genera 

 were. In 1839, one Curtis, knowing little, 

 critically, of diptera, in a general work on 

 British insects, capriciously designated the 

 nineteenth of Fabricius's species as the ' type ' 

 of Syrphus. In 1860, Schiner, perhaps the 

 ablest student of diptera, and one of the most 

 conscientious that we have ever had, subtracted 

 one of these original species, which happened 

 to be this ' type ' of Curtis, as the type of a 

 new genus Leucozona. The genus Syrphus, 

 the type of the family Syrphidse, with all its 

 eliminations, now comprises a hundred or two 

 species distributed in nearly all parts of th« 



