PROGEESS IN BIOLOGICAL INQUIRIES, 19 3 621 



reef. There is no doubt that without protection the beds will be 

 completely wiped out in a short time. 



The expedition brought back 310 live pearl oysters which were 

 planted in Kaneohe Bay near Honolulu. It is hoped that these 

 oysters will establish themselves in the new environment, which is 

 suitable for their growth and propagation, and will form a nucleus 

 of the first American pearl-oyster farm. 



With the view toward conservation of the only known pearl oysters 

 in the United States the Governor of the Territory of Hawaii has 

 issued an order forbidding for an indefinite period of time the tak- 

 ing of pearl oysters from any locality within the jurisdiction of the 

 Territorial government. 



INVESTIGATIONS OF MUSSELS AND POLLUTION IN INTERIOR 



WATERS 



The Columbia field unit, with a working staff of 11 under the di- 

 rection of Dr. M. M. Ellis, is lioused in a suite of eight rooms in the 

 new section of the Medical Building of the University of Missouri. 

 These rooms have been especially equipped by the University of 

 Missouri to meet the needs of fishery research, and the unit is recog- 

 nized by the University of Missouri as an adjunct to its graduate 

 school. 



FRESHWATER MUSSELS 



Glochidla and hreeding stock. — Thiough the cooperation of the 

 button manufacturers and various State officials over 6,000 gravid 

 female mussels were examined by this unit during the past year 

 and the condition of the glochidia studied with reference to disease, 

 stream pollution, and utilization for propagation purposes. This 

 work involved the handling of several thousand additional mussels, 

 as well, for correlations with age, locality, and general condition. 



Few glochidia suitable for propagation work were found, and the 

 effects of stream pollution on gravid mussels were discovered to be 

 far-reaching and serious, rather generally throughout the Mississippi 

 drainage. Two conditions in particular seem deserving of special 

 mention, viz, bacterial infection and chemical poisoning. 



Many marsupia, particularly from mussels collected in the Mis- 

 sissippi and tributaries below or near large cities, were found to have 

 black masses filling units of the marsupium normally occupied by 

 conglutinates of glochidia. Wlien the masses were opened they were 

 found to contain dead and disintegrating glochidia and to be heavily 

 infected with bacteria. Bacteriological studies of these masses 

 showed that in addition to the usual bacterial flora to be expected in 

 any decomposing mass of tissue, one particular organism, similar in 

 many respects to the well-known Bacillus p^^oteus, was recovered as 

 the principal' organism from this mass. Experimental work is now 

 in progress to determine whether this particular bacillus is of pri- 

 mary or secondary importance in the production of these lesions 

 in the brood pouches of mussels. It has been noted that the glochidia 

 in conglutinates adjacent to these black masses are less reactive 

 than normal glochidia, often being entirely unreactive, and that this 

 black mass spreads through the marsupium once the condition ap- 

 pears in a mussel, thus sterilizing the mussel as far as natural repro- 

 duction is concerned. These bacteriological' studies are being con- 

 tinued in connection with the other pollution studies mentioned below. 



