PROGRESS IN BIOLOGICAL INQUIRIES, 1934 399' 



plete life cycle of the black skimmer, Rhi/nchops nigra. The project 

 was carried out under the supervision of Dr. Alice L. lirown, with tlie 

 assistance of M. Way nick, A. L. Bason, A. S. Sherrill, B. Arnold, 

 and L. Jarrett, of the North Carolina College for Women; I. Bolick, 

 University of North Carolina ; and \l. L. Collie, of the North Caro- 

 lina State Museum. Particular attention was given to the develop- 

 ment of the emhryo, growth, and morphology of the mandibles and 

 the dilFerenliation of sex. Material for these studies was obtained 

 from the rookeries of the black skinnner on the Georgia coast and 

 from several located in Pamlico Sound, N. C. 



The facilities of the station were also utilized by the United States 

 Chemical Warfare Service for tests of wood preservatives, and by the 

 Bureau's Division of Fishery Industries for experiments on the dura- 

 bility of net twines treated with different preservatives. Cooperative 

 tests were continued with the Woolsey Paint Co. in respect to the 

 antifouling value of copper paints, and with the Tropical Paint & 

 Oil Co. on the suitability of bakelite varnishes for marine use. 



Terrapin culture. — Operations for the propagation of the dia- 

 mondback terrapin, conducted in cooperation with the Division of 

 Fish Culture, were unusually successful during the summer of 1934, 

 when a record hatch of 12,446 young was obtained. In addition to 

 this number approximately 1,000 eggs, embryos, and j^oung terrapin 

 were supplied to investigators from Duke University and the State 

 University of Iowa for studies of development and possible control 

 of sex in this species. During the spring of this year 10,445 young 

 terrapin from the 1933 brood were distributed in southern coastal 

 waters in cooperation with the North Carolina Department of Con- 

 servation, the South Carolina State Board of Fisheries, and the 

 Georgia Department of Fish and Game. 



The system of propagation has recently been modified and improved 

 by simulating natural conditions, so as to permit hibernation of the 

 3'oung terrapin during the winter months in protected outdoor pens. 

 This arrangement has not only reduced the cost and labor of their- 

 care in a heated rearing house, as required previously, but has con- 

 siderably increased the number surviving the critical 9-month period 

 from hatching to liberation. It was first tried with the 1933 brood, 

 of which over 98 percent were grown to a suitable size for distribu- 

 tion. Though record low temperatures occurred during the hiberna- 

 tion period, the total losses of 3'oung terrapin in this brood amounted 

 to only 179. as compared with losses ranging from 700 to over 3,000 

 during previous years. 



The annual production of young diamondback terrapin at the 

 Beaufort station hatchery since 1930 has been as follows: 1930, 5,778; 

 1931, 5,500; 1932, 11,08G; 1933, 10,0C0; 1934, 10,445. These operations 

 have been successful from a practical standpoint since 1912 and have 

 provided over 70,000 terrapin for breeding purposes and restocking 

 of coastal areas. Since the consumption and market demand for 

 terrapin has increased considerably in the last 2 years, it is advisable- 

 that artificial propagation of this species be continued and expanded,, 

 and an effort made to develop State hatcheries for this purpose. 



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