688 C. E. McCLUNG 



end while diverging in the center. Figure-8 chromosomes are 

 such rings with a secondary divarication of the end opposite 

 the first producing a second ring at right angles to the primary 

 ring. (3) The definitive metaphase chromosomes reach their 

 forms by a condensation of similar figures in the prophase. (4) 

 No clear statement regarding position of the chromosomes in 

 spindle is given but figures show rings lying in the equatorial 

 plate and the statement is made that the 'author agrees with the 

 descriptions of McClung and his students. (5) A similar state- 

 ment may be made regarding the movements of the chromatids 

 in metaphase. (6) The relation of chromosomes to fibers is not 

 clearly stated. (7) In the anaphase the chromosomes pass to 

 the poles of the spindle as simple Vs. (8) The result of the first 

 spermatocyte mitosis is a longitudinal division of the chromosomes 

 and no division of the accessory chromosome. (9) The telophase 

 chromosom.es may be traced into the second spermatocyte and 

 later are divided along the second longitudinal cleft, while the 

 accessory chromosome divides lengthwise also. 



Meek' s work ( ' 1 1 ) deals with the case of Stenobothrus on ly . His 

 conclusions are that (1) while there appears to be a complete 

 loss of chromosome identity during the growth period, the same 

 series of sizes and shapes reduced to the haploid number 9, reap- 

 pears in the first spermatocyte metaphase and it is possible that 

 the chromosomes of this stage are formed by earlier conjugation 

 of homologous spermatogonial elements. (2) Each first spemia- 

 tocyte prophase chromosome is formed of four parts, and may 

 show a variety of shapes — crosses, rings, loops, figures of 8, etc. 

 (3) The metaphase chromosomes appear either as rods, or as 

 V's with more or less unequal arms. (4) On the first spermato- 

 cyte spindle the chromosomes are placed principally as extended 

 rods or crosses. (5) No clear account is given of the movement 

 of the chromatids in the m.etaphase. (6) There is no statement 

 regarding fiber attachment. (7) An account of the anaphase 

 chromosomes is not given. (8) The first spermatocyte division 

 is thought to be longitudinal. (9) In the second spermatocyte 

 a possible reduction division occurs, although it is conceived that 

 both sperm.atocyte divisions may be longitudinal. 



