V 



May 12, 1905.] 



study of the complete life history of the 

 species. 



Mr. B. A. Bean, curator of fishes in the 

 National Museum, and his assistant, Mr. 

 McKnew, spent two weeks at the labora- 

 tory, June 6-20, studying fishes and mak- 

 ing a collection of certain forms for the 

 National Museum. Mr. Bean went over 

 the Beaufort collection of fishes and very 

 kindly verified or corrected the doubtful 

 identifications of some of the specimens. 

 Tanks of alcohol were left by him at the 

 laboratory, with a request that specimens 

 of fishes taken this season, in duplicate, not 

 collected by him, be preserved for the Na- 

 tional Museum. This request was com- 

 plied with. 



Dr. J. I. Hamaker, professor of biology 

 in the Randolph-Macon Woman's College, 

 beginning August 18, spent two weeks in 

 general collecting and in making observa- 

 tions on actinians. 



Caswell Grave. 



SCIENTIFIC BOOKS. 

 Heredity of Coat Characters in Guinea Pigs 

 and Raiiits. By Professor W. E. Castle. 

 Carnegie Institution of Washington, Pub- 

 lication, No. 23. February, 1905. 

 This paper includes a careful account of the 

 color varieties of domesticated cavies or 

 guinea-pigs, of which the agouti, the yellow, 

 the chocolate, the black, the albino, the spot- 

 ted, the brindled, the roan and silvered, the 

 long-haired and the rough-coated forms are 

 described. Cross-breeding between many of 

 these types was carried out and a detailed 

 account of the results is given. Without at- 

 tempting to review all of the many impor- 

 tant results of this elaborate study of heredity 

 a few of the more unusual or salient points 

 may be indicated. 



Albino or white guinea-pigs' breed true, but 

 crossing experiments with pigs of different 

 colors show that individual albinos give dif- 

 ferent results, which is due, Castle believes, 

 to the presence, in a greater or less degree, 

 of latent pigment tendencies, which do not 



737 



show up except in crossing. Thus the albino 

 2002 when mated with red females invari- 

 ably produces offspring marked with black; 

 while albino c? 1999 similarly mated produces 

 only red (or yellow) offspring, never black 

 ones. From these and similar results Castle 

 makes a distinction between the two terms 

 latency and recessive. Latency " is a condi- 

 tion of inactivity in which a normally dom- 

 inant character may exist in a recessive indi- 

 vidual. It is questionable whether a recessive 

 character may ever be latent." Recessive is 

 used in Mendel's sense to designate a char- 

 acter " which disappears when brought by 

 fertilization into the same (hybrid) individual 

 with a contrasted ' dominant ' character, but 

 which is transmitted, distinct from the dom- 

 inant character, in half of the gametes formed 

 by the hybrid individual." 



As is well known pure albino animals have 

 pink eyes. This means that pigment is ab- 

 sent from the eyes as well as from the skin. 

 Now pure white guinea-pigs and mice are 

 known having black eyes. These are not al- 

 binos but ' spotted ' animals, in which the 

 pigment spots have been so far reduced as to 

 be practically obliterated, except in the eyes. 

 The black-eyed white animals that appeared in 

 Castle's experiments did not breed true, since 

 spotted offspring often cropped up. Whether 

 by prolonged selection they could be made into 

 a pure race can not be stated, but Castle 

 thinks it not impossible. When mated to 

 pure albinos spotted offspring are produced. 



Guinea-pigs with a rough coat are animals 

 whose hair is arranged in rosettes or * cow- 

 licks ' around certain centers. Nine such cen- 

 ters can be recognized in individuals with the 

 best developed rough coats. In crossing these 

 roughs with ordinary or smooth-haired forms 

 the rough character is dominant. Here we 

 have another interesting instance of a recently 

 acquired character dominating in the off- 

 spring. The rough character is as fully de- 

 veloped as in the rough parent. The off- 

 spring of these rough hybrids follow the Men- 

 delian ratio, provided the degree in which the 

 rough character is developed in the offspring 

 is left out of consideration. Just here, how- 

 ever, comes a curious result, that is of the 



SCIENCE. 



