330 



SCIENCE 



[N. S. Vol. XLIII. No. 1105 



Under the heading Brief Notes, Exhibition of 

 Specimens: Dr. O. P. Hay exhibited the skuU of a 

 walrus from the southern Atlantic coast of the 

 United States and called attention to other speci- 

 mens of walrus from localities now far south of 

 its present range. It was Dr. Hay's opinion that 

 the walrus had followed the retreating ice sheet 

 northward. Dr. L. O. Howard called attention to 

 the cluster-fly {Pollenia riidis), an insect resem- 

 bling the house-fly but collecting in houses in au- 

 tumn and leaving a yellow stain when crushed. 

 Its life history was unknown until recently a for- 

 eign entomologist has shown that the larvse are 

 parasitic in earthworms in France. Dr. Howard 

 is having large numbers of earthworms examined 

 for such larvEe, but so far without success. He 

 hoped that any one finding any grub parasitic in 

 earthworms would communicate with him. 



The first paper of the regular program was by 

 Dr. Charles H. T. Townsend, "Identification of the 

 Stages in the Asexual Cycle of Bartonella badUi- 

 formis, the Pathogenic Organism of Verruga, and 

 their Bearing on the Etiology and Unity of the 

 Disease. ' ' The author finds that the complete 

 asexual cycle of Bartonella can be interpreted from 

 the figures and descriptions published up to April, 

 1913, and prior to the inception of the verruga 

 work of Dr. E. P. Strong of the Harvard School 

 of Tropical Medicine, and his associates. The 

 six identifiable stages in these figures and descrip- 

 tions are as follows: 



I. Early soMzonts — Gastiaburfl & Eebagliata, 

 Sept., 1912, in liver and eruption-tissue (eruptive 

 phase) . 



II. Maturing scMeonts, III. Early merozoites, 

 IV. Elongated merozoites — ^Mayer, Rocha-Lima & 

 "Werner, April, 1913, in vascular endothelial cells 

 of eruption-tissue (eruptive phase). 



V. Immature gametes — ^Darling, 1911, in blood 

 (fever phase). 



VI. Mature gametes — ^Barton, 1905, in blood 

 (fever phase). 



Tne second and- last paper of the program was 

 by A. A. Doolittle "The Mississippi Eiver Dam 

 at Keokuk, la.; Its Effect upon Biological Con- 

 ditions, especially those of the Plankton. ' ' Mr. 

 Doolittle said: 



The Bureau of Fisheries has been examining the 

 new conditions caused by damming the Mississippi 

 Eiver at Keokuk, la., to develop electric power. 

 The level of Lake Cooper, as the impounded 

 waters are called, reaches northward for 54 

 miles, and must be maintained between 34 and 



40 feet above of the river gauge at Keokuk. In 

 the lower portion of the lake the gorge of the Des 

 Moines Eapids and its tributaries are filled. In 

 the middle portion much island and farm land with 

 standing forests are inundated. Water Persicaria 

 is becoming established here. In the upper por- 

 tion levees protect the threatened farm lands, 

 which are kept drained by pumping stations. 



There are present the usual characteristics of a 

 river-lake: increased regularity of water stages, 

 decreased current, decreased turbidity, establish- 

 ment of aquatic plants. The most obvious and im- 

 mediate efEects, biologically, are, destruction of the 

 famous mussels of the rapids, and interference 

 with the migration of fish. Plankton is greatly in- 

 creased; zooplankton in the Entomostracan species 

 Moina micrura, Diaphanosoma braehyura and 

 Cyclops viridis, phytoplaniton species in Converva, 

 Anabaena, Clathroeystis. Above the influence of 

 the dam 50 Emtomostracan individuals, more or 

 less, were present per cu. yd. throughout the sum- 

 mer. At Keokuk there were 1,500 in July, 270,- 

 000 in August, and 1,500 in early September, aver- 

 aging about 10,000 per cu. em. Green Algae was 

 present in traces in the river proper; at Keokuk 

 0.14 cu. cm. in July, 29 cu. cm. in August, and 5 

 cu. cm. in early September. Blue Green Algae in- 

 creased from traces in July to 2.5 cu. cm. in Au- 

 gust and September at Keokuk. The river below 

 the dam was enriched upwards of 100 times in 

 mid-season. In weedy waters heavy bodied. Bnto- 

 mostraca abounded; Sida Scapholeberis, Simoceph- 

 alus, with a maximum of 178,000 individuals per 

 cu. yd. whose volume was 23 cu. cm. Streams and 

 sloughs filled from the lake ripened earlier than 

 the lake, and maintained about 50,000 lake species 

 of Entomostraca per cu. yd. Self-fed tributaries 

 usually had plankton differing from that of the 

 lake, sometimes Protozoa (Euglena) dominant, or 

 Eotifers (Asplanchna) , or their own Entomo- 

 stracan forms. These could be traced into the 

 lake, but they did not persist there. It is evident 

 that there is a vast increase of fundamental food 

 for some species of fish or their young. The dis- 

 cussion was illustrated with map, diagrams and 

 slides showing conditions existing in the summer 

 of 1914. 



The paper was discussed by the chair, and by 

 Messrs. Coker, Marsh and William Palmer. 



The society adjourned at 10.10 p.m. 



M. W. Lyon, Je., 

 Recording Secretary 



