ANIMAL PRODUCTION. 569 



in the mule. There is considerable evidence that primary spermatocytes 

 make an attempt to eliminate some of the chromatin material. The chromo- 

 somes expelled by the cells appear to be those which were contributed by the 

 mother of the hybrid. Destruction as well as abnormalities in mitosis seems 

 to be restricted to the primary spermatocytes. Most of the cells disintegi-ate 

 during the prophase, especially during the period of synapsis. Others meet 

 their fate in the metaphase or early anaphase stages. The remaining few that 

 survive the anaphase succumb soon after, and no secondary spermatocytes nor 

 spermatids, and consequently no spermatozoa, are formed and the hybrid 

 remains sterile. There are no authentic cases on record showing that fertility 

 ever occurs in this hybrid." 



A bibliography is appended. 



The coloring' of hens' eggs by crossbreeding and the duration of these 

 color changes, A, von Tschermak (Biol. Centhl., 35 (1915), No. 1, pp. 46-63, 

 figs. 3). — The author reports cases of color xenia and telegony in hens' eggs 

 and comments on the causes of these phenomena. 



Production and composition of the eggs of different breeds of poultry, 

 P. F. Lev^que and L. J. Ponscaeme (Ann. Ecole Nat. Agr. Grignon, 4 (1913), 

 pp. 38-42). — Data are given showing the number, weight, and composition of 

 the eggs of different breeds of poultry, and the influence of the shape of the 

 egg on the amount of yolk, white, and shell. 



It appears that generally there is more yolk and shell in the long egg but 

 less white than in the round egg. On the average the desiccated egg contents con- 

 tained 2.949 per cent of P2O5, of which the yolk contained 2.618 per cent; 18.443 

 per cent of nitrogen, of which the yolk contained 5.028 per cent ; and 0.0953 per 

 cent of Fe203, of which the yolk contained 0.0627 per cent. 



Cost of raising Leghorn pullets, A. G. Philips (Jour. Amer. Assoc. Instr. 

 and Invest. Poultry Hush., 2 (1916), No. 5, pp. 39, 40). — Experiments at the 

 Indiana Experiment Station are referred to which indicate that it costs an 

 average of 38.9 cts. to produce a pullet to laying age, including practically all 

 expenses. The results also indicate that it takes from 4 to 5 eggs to produce a 

 pullet. 



Poultry raising in Colorado, W. E. Vaplon (Colorado Sta. Bui. 213 (1915), 

 pp. 15, figs. 6). — A general discussion of methods of feeding, care, and manage- 

 ment of poultry under Colorado conditions. 



Methods of poultry management at the Maine Agricultural Experiment 

 Station, R. Peael (Maine Sta. Doc. 515 (1916), pp. 98, figs. 27).— Tliis is an en- 

 largement and revision of Farmers' Bulletin 357 (E. S. R., 21, p. 274), contain- 

 ing additional data on poultry hygiene and sanitation, brooders, feeding the 

 laying pullets, natural enemies of poultry, use of hen manure, etc. 



Duck raising, A. R. Lee (U. S. Dept. Agr., Farmers' Bui. 697 (1915), pp. 22, 

 figs. 13). — This treats of the various breeds of ducks and their feed, care, 

 management, and preparation for market. 



Ancestry of the goose (Jour. Heredity, 7 (1916), No. 1, pp. 39-45, figs. 4). — 

 The author contends that the ordinary domestic breeds of geese are descend- 

 ants with slight modifications of the graylag goose, still found wild in most 

 parts of the Old World. It is thought that breeding in captivity must have 

 begun at an early date. 



Pheasant farming, G. M. Simpson (Oregon Fish and Game Com. Bui. 2 

 (1914), pp. 50, pi. 1, figs. 27). — This booklet treats of the varieties of pheasants 

 and their breeding, care, and management for commercial purposes. 



Fish ponds on farms, R. S. Johnson and M. F. Stapleton (U. S. Dept. Com., 

 Bur. Fisheries Doc. 826 (1915), pp. 28, pis. i9).— This treats of the utilization 

 31501°— No. &— 16 6 



