(136 



THE AMERICAN NATURALIST [Vol.L 



grandams and offspring 1 , but it is impossible to assert any trust- 

 worthy correlation for the other grandparents. 



Marshall 34 while emphasizing the importance of the hereditary 

 factor in multiple births in sheep, adduces evidences for the 

 great importance of feeding as a factor in the production of 

 twins and triplets. His figures certainly show great and con- 

 sistent differences in the produce of flocks which have received 

 different treatment at and preceding tupping time. Unfortu- 

 nately differences in breed may, but do not necessarily, cast some 

 doubt on the interpretation of the data. The problem which he 

 has attempted to solve by the analysis of schedules received from 

 flock masters certainly deserves experimental study. Such in- 

 vestigations have actually been begun by Evvard who in a first 35 

 and second 36 and third 37 report on experiments with swine has 

 given the results of various feeding upon the vitality of the off- 

 spring. Discussion of the data as they are presented in these 

 papers falls outside the scope of a biometric review. Such work 

 is, however, of great importance at a period of science in which 

 heredity as contrasted with environment is apt to be assumed to 

 be an all-important factor. It is a pity that such experiments 

 as these of Marshall and Eward can not be carried out in close 

 cooperation with experts on the physiology of nutrition, so that 

 differences in rations might be arranged on a uniform scale. 



J. Arthur Harris 



ON A BARNACLE, CONCHODERMA VIRGATUM, AT- 

 TACHED TO A FISH, DIODON HYSTRIX 1 



A specimen of the "sea porcupine," Diodon hystrix Linn., 

 seen swimming near the surface and seeured with a dipnet, was 



s* Marshall, P. H. A., "Fertility in Scottish Sheep," Trans. High. Agr. 

 Soc. Scotland, V, 20: 139-151, 1908. 



ss Evvard, J. M., "Nutrition as a Factor in Fetal Development," Troc 

 Amer. Breed. Ass., 8: 549-560, 1912. 



se Eward, J. M., "Some Factors affecting Fetal Development," Troc 

 Iowa Acad. Sci., 20: 325-330, 1913. 



37 Evvard, J. M., A. W. Dox and S. C. Guernsey, "The Effect of Calcium 

 and Protein Fed Pregnant Swine upon the Size, Vigor, Bone, Coat and 

 Condition of the Offspring," Troc. Iowa Acad Sci 21- 269-278, pi. 31-35, 

 1914. 



i Contributions from the Bermuda Biological Station for Eesearch, No. 50. 



