26 



SCIENCE 



[N. S. Vol. XL. No. 1018 



the Women's Affiliated Colleges of Delaware, 

 at l^ewark, Delaware. 



Albeet G. Hogan, Ph.D. (Tale), has been 

 appointed assistant in animal nutrition at the 

 Kansas Agricultural Experiment station, 

 Manhattan, Kansas. 



At the University of Indiana Dr. Kenneth 

 P. Williams has been promoted from instruc- 

 tor to assistant professor of mathematics. 



Miss Susan Rose Benedict, Ph.D. (Michi- 

 gan), has been made associate professor of 

 mathematics at Smith College. 



DISCUSSION AND COBEESPONDENCE 



TYPES OF BIRD GENERA LIMNOTHLYPIS NEW GENUS 



Some years ago in discussing the fixing of 

 types for the genera of North American Birds 

 the writer called attention in these columns 

 to the fact that certain names would have to 

 be changed if the principal of " type by sub- 

 sequent designation " adopted by the Inter- 

 national Zoological Congress were adopted. 

 This view was opposed by Dr. J. A. Allen on 

 the ground that in his interpretation of the 

 Code a subsequent designation was not valid 

 if the species designated was already the type 

 of another genus. The point raised was one 

 of such importance that it was placed before 

 the International Commission for an opinion 

 and this has just been rendered and the 

 writer's stand has been endorsed. As the 

 matter is one upon which many systematic 

 workers have been in doubt, it seems desirable 

 to call special attention to the decision. 



Incidentally one genus of North American 

 birds is left without a name by the operation 

 of this ruling. 



JSelinaia Audubon, 1839, contained origi- 

 nally two species, the worm-eating warbler 

 H. vermivora (Gm.) and Swainson's warbler, 

 H. swainsonii (Aud.). The name has been 

 used universally for the latter but the first 

 designation of a type by Gray fixed it upon the 

 former, and in spite of the fact that this was 

 already the type of Helmitheros it thereby be- 

 comes the type of Helinaia, the latter name 

 being thus a synonym of Helmitheros Rafin- 

 esque. As no other generic name is available 



for Swainson's warbler I would propose Limno- 

 thlypis'^ with Sylvia swainsonii Audubon as 

 its type. Wither Stone 



Academy op Natural Sciences, 

 Philadelphia 



mutation 



In a recent number of Science Professor 

 Edward C. Jeffrey^ raises objections to the 

 concept mutation upon the ground that the 

 phenomena in (Enothera lamarchiana, which 

 de Vries described as mutation, are not mu- 

 tation, this species being, as Bateson long ago 

 suggested, a hybrid form. There seems to be 

 about as much cogency in this argument as 

 there would be in the claim that metagenesis 

 is not a true concept because in Salpa, the 

 form in which de Chamisso^ first discovered it, 

 it does not exist.* 



The distinction between heritable variations 

 (mutations, stable variations, "discontinuous"* 

 variations) and non-heritable variations (fluc- 

 tuating, unstable, " continuous "* variations) 

 seems to be clearly established experimentally, 

 and the interpretation of the former as germi- 

 nal and the latter as somatic in origin, seems 

 to have much in its favor. 



Is not Professor Jeffrey's objection some- 

 what in the nature of a quibble? 



Maynaed M. Metcalf 



a new locality and horizon for 

 pennsylvanian vertebrates 

 Finds of Pennsylvania vertebrates are al- 

 ways interesting and important and are doubly 



1 Xt/ivTi a marshy lake and 9\vins an ancient bird 

 name. 



i"Tlie Mutation Myth," Science, XXXIX., 

 No. 1005, April 3, 1914. 



2 A de Chamisso, ' ' De animalibus quibnsdum e 

 elasse Vermium linneana in eircnmnavigatione 

 terrae, " etc. Fasciculus primus, De Salpa. Ber- 

 olini, 1891. 



3 W. K. Brooks, ' ' Chamisso and the Discovery 

 of Alternation of Generations," Zool. Ameiger^ 

 Jahrg. 5, 1882. 



* A poor term, for their heredity, not their de- 

 gree of divergence from the parent stock, is the' 

 salient point. 



