January 26, 1906.] 



SCIENCE. 



153 



sporogenesis agree in all essentials with those 

 already described for the Ascomycetes (Faull, 

 * Contributions from the Cryptogamic Labora- 

 tory of Harvard University,' LXI., in which 

 there is a complete bibliography). Details 

 and further researches in this group, which 

 heretofore has not been subjected to micro- 

 tonic methods, will be described in a forth- 

 coming paper. 



J. Horace Faull. 

 Ujniveesity of Toronto, 

 December 2, 1905. 



INBREEDING, CROSS-BREEDING AND STERILITY IN 

 DROSOPHILA. 



A SERIES of breeding experiments with the 

 common pomace-fly, Drosophila ampelopMla 

 Loew., conducted during the past five years 

 principally by my pupils and still in progress, 

 has yielded certain results which it is the pur- 

 pose of this note to summarize. A fuller ac- 

 count will soon be published elsewhere. Those 

 who have taken part in the work are Thomas 

 Ordway, Austin H. Clark, F. W. Carpenter, 

 S. 0. Mast, "W. M. Barrows and myself. The 

 part of each will be indicated in the final 

 publication. The more important conclusions 

 reached may be stated thus: 



1. Inbreeding probably reduces very slightly 

 the productiveness of Drosophila, but the pro- 

 ductiveness may be fully maintained under 

 constant inbreeding (brother with sister) if 

 selection is made from the more productive 

 families. 



2. In crosses of a race of low productiveness 

 and frequent sterility (race A) with a race of 

 high productiveness (B) it has been found 

 that a female of race A does not have her 

 fecundity increased by mating with a male of 

 race B, and conversely, a female of race B 

 does not have her fecundity diminished by a 

 mating with a male of race A. Hence every 

 male not actually sterile furnishes an abun- 

 dance of functional spermatozoa. 



3. The cross-breds produced by the mating, 

 B female X ^ male, are all of high product- 

 iveness. 



4. The cross-breds produced by a mating 

 A female X B male are usually, but not al- 

 ways of high productiveness. 



5. The children of both sorts of cross-breds 

 (see 3 and 4) are some of high productiveness 

 like race B, others of low productiveness like 

 race A. 



6. Low productiveness is inherited after the 

 manner of a Mendelian recessive character in 

 certain of the crosses made, skipping a genera- 

 tion and then reappearing. In other cases it 

 has failed to reappear in generation F„, indi- 

 cating its complete extinction by the cross. 

 In a few cases it has failed to be dominated 

 by high productiveness in generation F^. In 

 such cases the female parent has always been 

 of race A. Hence low productiveness (or 

 sterility) of the female may be transmitted 

 directly through the egg from mother to 

 daughter, but only indirectly through the 

 sperm, the character skipping a generation. 



7. A cross between two races, one inbred 

 for thirty or more generations and of low 

 productiveness, the other inbred for less than 

 ten generations and of high productiveness, 

 produced offspring like the latter in product- 

 iveness, but not superior to it. 



8. The same two races crossed after an addi- 

 tional year of inbreeding (about twenty gen- 

 erations) produced offspring superior to either 

 pure race in productiveness. 



9. Inbreeding does not affect the variability 

 in number of teeth on the sexual-comb of the 

 male. 



10. This character is closely correlated with 

 size. 



W. E. Castle. 

 Zoological Laboratory, Harvard College, 

 January 11, 1906. 



GVRRETSlT NOTES ON METEOROLOGY. 

 AUSTRALIAN DAILY WEATHER MAPS. 



In 1904 the Public Schools Associations in 

 New South Wales appealed to the Sydney 

 Daily Telegraph to publish daily a weather 

 map for Australia in order that the pupils in 

 the schools might be given instruction in 

 meteorology by means of the maps. The 

 Telegraph thereupon applied to the Sydney 

 Observatory for a daily chart, to be supplied 

 not later than 2 p.m., in order that it might 

 appear in the evening editions which reach the 

 country in time for use in the schools the 



