BIOLOGY. 323 



food-supply of our edible fishes, of which the diatoms are known to 

 form an important part, there is need also for this work in connection 

 with certain oceanographic researches, especially for the purpose of 

 assisting in the determination of the trend and extent of certain ocean 

 currents by means of the particular species of diatoms these currents 

 transport. It is evident that this contributory service can not be 

 rendered until the different diatom floras of the coasts swept by these 

 currents have been carefully studied and recorded. At present our 

 knowledge of the diatoms of our eastern seaboard is very meager, and 

 it ought to at once receive such attention as will bring it to some 

 degree of completeness comparable with that of the shores of Europe. 

 It is hoped that similar studies may include the coasts of the Gulf of 

 Mexico and of the Pacific States, for the diatoms of these regions are 

 even less known to science. 



The geological relationships existing between the numerous fossil 

 diatom deposits distributed over the United States deserve the study 

 of a competent diatomist, to supplement the investigations of the 

 technical geologist. A large amount of material is now available for 

 this purpose. It is proposed to take this work up as soon as other 

 lines of research already begun have been completed. 



Several of the large and widely distributed genera of diatoms are 

 represented in only a fragmentary way throughout the literature 

 bearing on this subject. This literature is itself rare and difficult of 

 access; and publication of studies of these cosmopolitan genera will be 

 of advantage to this part of marine biological science. It is intended 

 that illustrated monographs will be prepared from time to time along 

 these lines. 



It is well to state, in connection with this preliminary report of plans, 

 that the study of these minute and delicate organisms requires a differ- 

 ent technique from that of any other line of investigation. Compara- 

 tively few scientific students have given to it the time and effort neces- 

 sary to master it. It happens also that, of the small number who have 

 devoted themselves to this field, an unusually large proportion has 

 recently died. It is consequently opportune that these investigations 

 are now being taken up, and under such auspices as will insure the 

 proper training of new workers who will be fitted to carry forward 

 future investigations in so speciaUzed and uncommon a field of scien- 

 tific research. 



Castle, W. E., Harvard University, Cambridge, Massachusetts. Continua- 

 tion of experimental studies of heredity in small mammals. (For previous 

 reports see Year Books Nos. 3-17.) 



The principal subjects under investigation during the past year have 

 been: (1) the phenomenon of linkage in heredity, whereby characters 

 go together or stay apart in genetic transmission; (2) the method of 



