PEOGEESS IN BIOLOGICAL INQUIRIES, 19 31 527 



Steinberg, director of the Toledo Hospital, the effect of bacterial 

 toxins on various marine forms; Dr. Ezda Deviney, of the University 

 of North Carolina, reffonorntion of Ascidians, particularly with re- 

 spect to the specific colls in Perophora that are of greatest importance 

 in this process; Dr. C. D. Beers, of the University of North Carolina, 

 structure and life history of two colonial protozoa (Vorticellidae) ; 

 Rebecca AYard, of Judson College, invertebrate marine fauna of 

 this region and early development of several Echinoderms; Dr. Bert 

 Cunningham, of Duke University, relationship of temperature to the 

 rate of embryonic development of diamond-back terrapin. 



The facilities of this station were also utilized by the investigators 

 of the United States Chemical Warfare Service, who tested the value 

 of various oils as a preventive of the destruction of wood by marine 

 borers. In cooperation with the Eastman Kodak Co. an educa- 

 tional motion-picture film was prepared showing photomicrographic 

 studies of the development of the oyster and the scientific methods 

 of oyster cultivation that have been developed by the Bureau of 

 Fisheries. 



Terrapin culture. — The propagation and distribution of the dia- 

 mond-back terrapin is meeting with greater success each year. In 

 the spring of 1931 about 5,500 year-old terrapins from the 1930 

 brood were turned over to the North Carolina Department of Con- 

 servation and Development for liberation in the coastal waters of 

 this region. The 1931 hatch, amounting to 12,152 young, has ex- 

 ceeded all former records and is over 25 per cent greater than the 

 largest j^revious hatch of 8,931 in 1928. 



Growth studies and feeding experiments with the 1930 brood were 

 made during the first half of the year by Dr. Samuel F. Hildebrand. 

 Several of these experiments extended over three seasons and 

 yielded noteworthy results that are of value in the culture of this 

 species. Of the various foods and mixtures of foods used, oysters 

 fed alone produced the most rapid growth in the 1930 brood, with 

 a mixture of oysters and fish a close second. Fresh fish fed alone 

 promoted a fair rate of growth and is the cheapest and most easily 

 prepared terrapin food available at Beaufort. It was shown again 

 that salt water is a slightly better medium than fresh water for 

 young terrapins in the brooder house. 



Various diseases develop during the period that the young are 

 cared for in the rearing house and greatly reduce the total pro- 

 duction of year-old individuals. The disease, designated as " sores," 

 for want of a better teiTn, which has been present among young 

 winter-fed terrapins from year to year was rather more prevalent 

 than usual in the 1930 brood and in a few tanks reached epidemic 

 proportions. Among 7,054 animals taken care of in the brooder 

 house, 6 per cent diecl of this disease. " Soft shell," associated with 

 a failure to feed and to grow, caused 14.2 per cent of deaths, and 

 all other causes 1.6 per cent, making a total death rate of 21.8 per 

 cent. This is near the average death rate for winter-fed animals 

 from 1920 to 1929, inclusive. 



In rearing the large 1931 brood particular attention has been given 

 to these diseases and studies made to determine their cause and ef- 

 fective method of control. Shortly after the young were trans- 

 ferred to the rearing house there appeared a serious outbreak of the 



