Mat 13, 1921] 



SCIENCE 



463 



less the mutation occurred in a cell generation 

 earlier than that in which the egg itself was 

 differentiated no other germ cells of the 

 parent or collaterals of the eyeless individual 

 should hear the factor for eyelessness. 



Observation of the occurrence of an eyeless 

 mutant and the transmission of this char- 

 acteristic would be of great interest as bear- 

 ing upon the probable origin of eyeless cave 

 animals. As is well known, many cave ani- 

 mals, particularly crustaceans, are without 

 eyes or have extremely degenerate eyes. 



It has been suggested that such cave forms 

 may have arisen by " orthogenesis " (many 

 small mutations) or, by implication, jwssibly 

 by a single large mutation.^ 



Eyelessness in these forms is associated 

 with lack of body pigment. Pigmentless ani- 

 mals, such as cave amphipods for example, 

 may suffer deleterious effects if they come 

 under the influence of the actinic rays of 

 sunlight. Such animals are conspicuous and 

 an easy prey to their natural enemies. In so 

 far as a general vision may aid such organ- 

 isms in reaching a suitable locality for secur- 

 ing food eyeless individuals are at a disad- 

 vantage in the open in competition with eyed 

 individuals. On the other hand in caves and 

 similar situations they are shielded from 

 light, are not rendered conspicuous by their 

 whiteness and are at no disadvantage in com- 

 petition for food. It would seem that they 

 have become segregated in caves and other 

 retired situations because they can survive 

 there and are unable to do so elsewhere. 



The occurrence in Drosopliila of a " bar- 

 eyed " mutant (eye much reduced in size and 

 in effective elements) and an " eyeless " 

 mutant (in most cases not really eyeless but 

 eyes more or less rudimentary) lends credence 

 to the theory that eyeless cave animals, or 

 such animals with very defective eyes, may 

 have arisen as the result of mutations. One 

 does not however lose sight of the fact that 

 the eyeless daphnid mentioned may have 

 arisen from a disturbance in development 

 such as the writer has seen in eyeless sala- 



1 Banita, Carnegie Institution of Washington, 

 Puhlieatiion No. 67, 1907. 



mander larvae and as have been found in 

 other experimentally treated material. Of 

 course in such cases one does not in general 

 (Guyer's rabbits possibly form a notable excep- 

 tion) anticipate any degree of inheritance 

 whatever, even if the abnormal individuals 

 were viable and capable of producing young. 

 In the case of this eyeless daphnid however 

 there were embryos in the brood chamber and 

 there seemed every reason to believe that it 

 possessed the normal capacity for producing 

 young. 



Arthur M. Banta 



THE EASTER MEETING OF THE AMER- 

 ICAN MATHEMATICAL SOCIETY 

 AT CHICAGO 



The sisteentli regular Western meeting of the 

 American Mathematical Society was held at the 

 University of Chicago on Friday and Saturday, 

 March 25 and 26, 1921. The meetings were at- 

 tended by over sixty persons, among whom were 

 fifty-three members of the socdety. 



The session of Friday afternoon was devoted 

 to a leoture by Professor Dunham Jackson on 

 "The general theory of approximation by poly- 

 nomials and trigonometric sums. ' ' 



It was voted at this meeting that the Christmas 

 meeting of the Chicago -Section be held in To- 

 ronto, in afBliation with the Convocation week 

 meetings of the American Association for the Ad- 

 vancement of Science. 



A dinner at which forty-seven persons were 

 present was held at the Quadrangle Club on Fri- 

 day evening. 



At the sessions <ot Friday and Saturday fore- 

 noons, the following papers were presented: 



1. I. J. Schwatt, "On the expansion of powers 



of trigonometric functions. ' ' 



2. I. J. Schwatt, "On the summation of a trigo- 



nometric power series." 



3. W. B. Ford, "A disputed point regarding the 



nature of the continuum. ' ' 



4. Mayme I. Logsdon, "The equivalence of pairs 



of hermitian forms. ' ' 



5. C. C. MaxjDuffee, "Invariants and vector co- 



variants of linear algebras without the as- 

 sociative law." 



6. E. J. Wilczynski, "Some projective generali- 



zations of geodesies." 



7. W. L. Hart, "SummaJble infinite determi- 



nants. ' ' 



