REPORT OF NATIONAL MUSEUM, 1922. 67 



appeared during the year. Prof. Max M. Ellis, of the University of 

 Missouri, collaborator, is at present working up a report upon a 

 cross-continent section of the North American Discodrilid fauna, a 

 study based upon several thousand specimens collected by himself 

 from 25 different localities between Indiana and the Yellowstone 

 National Park. Doctor Ellis has promised a first set of these worms, 

 including types, to the Museum. Two reports, the result of the labors 

 of Harry K. Harring, custodian of the Rotatoria, have been pub- 

 lished during the year, the first dealing with the Rotatoria of the 

 Canadian Arctic Expedition, and the other, in collaboration with 

 Frank J. Myers, being a first part of a report on the rotifers of Wis- 

 consin. Work upon the second part of the latter report is being 

 continued. 



Dr. William H. Dall has monographed the marine shell-bearing 

 mollusks of the Hawaiian Islands, a work which, unless new material 

 comes in, has been completed except for part of the figures. John B. 

 Henderson has studied the Turritidae of the western Atlantic with 

 a view to publishing a monograph of this group. He has also worked 

 on a monograph of the Antillean land and fresh-water mollusks, a 

 list of the mollusks collected by the Barbados- Antigua expedition of 

 the State University of Iowa, and (in conjunction with Doctor 

 Bartsch) on the mollusk fauna of the vicinity of Beaufort, N. C. 

 Doctor Bartsch has completed a monograph of the American ship- 

 worms, to be published as Museum Bulletin No. 122. It is hoped that 

 this bulletin will be of assistance to engineers and water-front prop- 

 erty owners and of interest to scientists in general. Some progress 

 has been made on special groups of African, Philippine, Middle 

 American, and Antillean mollusks, and with Mr. Henderson on the 

 mollusk fauna of the Beaufort region. Doctor Bartsch's experiments 

 in heredity were continued at the Marine Biological Laboratory of the 

 Carnegie Institution at the Tortugas, Fla. This work is described 

 in a paper entitled " Cerion Breeding Experiments," which will be 

 published in the Smithsonian Exploration Pamphlet. William B. 

 Marshall, apart from his very exacting routine duties, has found 

 time to complete an investigation of the mollusks of the genus 

 Corbicvla of South America. He has also completed a paper on two 

 new Diplodons of Uruguay and has continued his studies of the South 

 American fresh-water mussels. 



Austin H. Clark has prepared reports on the brittle stars of 

 Curasao, on the echinoderms of the Cheticamp Expedition, 1917, and 

 on the echinoderms collected by Frits Johansen in James and Hud- 

 son Bays in the summer of 1920. He continued work on the Ingolf 

 report and on part 3 of Bulletin No. 82, both of which are nearing 

 completion. 



