252 GENETICS [Bot. Absts., Vol. VI, 



ing and heterotypic, eighteen bivalent chromosomes and one accessory are present. Conju- 

 gation is probably parasynaptic. The accessory chromosome passes undivided to one pole, 

 thus yielding two types of secondary spermatocytes. The division of the chromosomes, 

 including the accessor}', in secondary spermatocytes is equal and homotypic. Occasionally, 

 incomplete fusion of two adjacent chromosomes occurs, thus reducing the count. — The 

 centrosome behaves much as it does in man, as described by Meves. A chromatoid cor- 

 puscle appears during the growth stage, but is probably cast off from the spermatozoon in a 

 mass of cytoplasm. Mitochondria appear during the postsynaptic stage. Most of them 

 mass and give rise to a body resembling the "Nebenkern" in insects. Ultimately this mass 

 comes to occupy the middle part of the spermatozoon. — M. F. Guyer. 



1722. Mastti, Kiyoshi. The spermatogenesis of domestic mammals. II. The spermato- 

 genesis of cattle (Bos taurus). Jour. Coll. Agric. Tokyo Imperial Univ. 3: 377-403. 3 pi., 

 1 fig. 1919. — Amitotic nuclear divisions (not followed by division of the cell-body) occur more 

 frequently in the spermatogonia of embryos and of very young animals than do mitotic divi- 

 sions. Such amitosis is regarded as characteristic of degenerating cells which are destined to 

 supply nutriment to the germ cells. The resting nuclei of both penultimate and ultimate 

 spermatogonia are characterized by one large nucleolus and a small chromatin mass. The 

 spermatogonial number of chromosomes is thirty-three. Conjugation is probably telo- 

 synaptic. Sixteen bivalent and one univalent (the accessory) chromosomes result. The first 

 spermatocyte division is reducing. The accessory passes undivided to one pole. The 

 second division, which includes the accessory, is a simple equation-division. The chromatin 

 nucleolus, visible through the growth period and the reduction division, is identified as the 

 accessory chromosome. — Incomplete fusion of adjacent chromosomes sometimes occurs in 

 the secondary spermatocytes; so that only nine or ten chromosomes can be counted in such 

 cells. Numerous mitochondrial granules appear during the growth period and thereafter 

 behave similarly to those of the horse. A chromatoid corpuscle is absent or present infre- 

 quently. The centrosome of the spermatid divides, and one of the resulting centrosomes 

 comes to lie close to the nucleus — the other a short distance behind it. The axial filament 

 arises from the latter. The idiosome first appears during the growth stage. In the spermatid 

 it seems to have no connection with the centrosome. — M. F. Guyer. 



1723. Meek, C. F. U. Chromosome dimensions. Proc. Roy. Soc. London 91: 157-165. 

 1920. — Correlation between chromosomes and somatic complexity of animals. Author 

 reviews his own conclusions of 1912 and those of Farmer and Digby, 1914. He also presents 

 additional observations, made without measurements, upon chromosome length, diameter, 

 and total chromatin volume in spermatogonial and spermatocyte complexes of several species 

 of widely separated groups. His final conclusions are that there is no correlation between 

 degree of somatic complexity of animals and their chromosome number, length, or diameter, 

 nor with the total chromatin volume of their complexes. — C. L. Parmenter. 



1724. Metz, C. W. Observations on the sterility of mutant hybrids in Drosophila virilis. 

 Proc. Nation. Acad. Sci. [U. S.] 6:421-423. July, 1920.— Three sex-linked and probably 

 allelomorphic mutants in Drosophila virilis — rugose, glazed, and wax (all affecting the eyes) — 

 have been shown to form a graded series in respect to their morphological characteristics 

 and in respect to fertility, the females of the last two being sterile. In any hybrid involving 

 rugose and either of the others, the first named mutant is dominant as to somatic manifes- 

 tations; but the females are sterile like the glazed or wax females. Thus the order of domi- 

 nance of somatic manifestations is the one given, but the reverse is true of fertility. Pre- 

 viously rugose and glazed were spoken of as incompatible, but this was before the sterility of 

 glazed females was noted. — H. H. Plough. 



1725. Metz, Charles W. The arrangement of genes in Drosophila virilis. Proc. Nation. 

 Acad. Sci. [U. S.] 6: 164-166. April, 1920.— In connection with Castle's three-dimensional 

 model of the sex-linked genes of Drosophila virilis from data of Metz, certain predictions were 

 made as to the probable location of the genes for frayed, hairy, rugose and glazed; and it was 



