PROCEEDINGS OF THE ACADEMY AND AFFILIATED 



SOCIETIES 

 BIOLOGICAL SOCIETY 



599TH MEETING 



The 599th regular meeting of the Biological Society of Washington 

 was held in the Assembly Hall of the Cosmos Club on October 18, 191 9; 

 called to order at 8.30 p.m. by Vice-President N. Holuster. Thirty- 

 six persons were present. 



The following informal communications were presented: 



R. W. ShufeldT: Exhibition of a young specimen of the wood tortoise 

 [Clemmys insculpta (Le Conte)] secured recently near Bennings, in 

 the District of Columbia. An adult animal was shown for comparison. 



Wm. Palmer: Further remarks upon the occurrence of the wood 

 tortoise in the District of Columbia. Three were reported from the 

 Eastern Branch, one from Plummers Island and another from a marshy 

 spot below Plummers Island. One taken by E. A. Preble is now in 

 the District Collection in the National Museum. Three young tor- 

 toises of this species were taken from the stomach of a copperhead 

 killed by F. C. Craighead. 



P. Bartsch: Note on the extraordinary tameness of red-breasted 

 nuthatches observed on Mt. Monadnock, New Hampshire. 



The regular program consisted of three communications. 



J. S. Outsell: Use of selective screens in studies of oyster larvae. 

 Mr. Outsell stated that in studies of larval oysters the Bureau of Fish- 

 eries has developed a method of collecting material from a power boat, 

 by means of a pump having a capacity of several gallons a minute. 

 The water thus secured is strained through a screen made of bolting 

 silk. Catches are made in desired localities, placed in suitable con- 

 tainers, and transferred to the laboratory. There the material is 

 passed through a series of six wire-gauze screens of graduated fineness. 

 Much undesired material is removed by the two upper screens that are 

 coarse enough to permit the passage of the oyster larvae. The four 

 remaining screens automatically separate the larvae according to size. 

 Dail}^ studies of the condition of the segregated larvae make it possible 

 to foretell the time when the larvae will set. As the method of col- 

 lection is quantitative, it is possible also to show where the larvae are 

 drifted by tidal currents and thus to indicate the location of the culch 

 when the proper time arrives. Discussion by Dr. P. Bartsch followed. 



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