440 



SCIENCE 



[N. S. Vol. XLI. No. 1055 



Janns green produces coagulation phenomena 

 in living protoplasm and therefore should not be 

 used to identify mitochondria. 



The mitochondria are rigid structures. In the 

 Orthopteran germ they all change from granules 

 to strands, they coalesce, they disappear and re- 

 appear and may be expressions of changes in the 

 physical states of the cytoplasmic colloids. 



The chromosomes behave almost as do the 

 mitochondria. In the hyaline resting nucleus they 

 appear in the form of granules ranged about a 

 hyaliae resistant core. The granules coalesce to 

 form the homogeneous body of the metaphase 

 chromosomes. In telophase the chromosomes swell 

 and disappear. Some internal chemical condition 

 may exist which so regulates the physical states 

 of the nuclear colloidsl that a constant nmnber of 

 chromosomes periodically appears. 



Spermatogenesis in Faratettix : Maky T. Haeman. 



1. The chromosomal complex of the spermato- 

 gonial divisions of Faratettix leuoonotus — leuco- 

 thorax consists of thirteen rod-shaped chromo- 

 somes which may be divided into two groups, one 

 consisting of four large chromosomes and the 

 other of nine smaller ones. 



2. Eight of the smaller chromosomes are 

 straight rods; one of the smaller ones and all of 

 the larger ones are U-shaped. The chromosomes 

 do not form equal pairs. 



3. In the metaphase stage the chromosomes are 

 at right angles to the spindle fibers, but in the 

 anaphase they are parallel to them. 



4. One chromosome is always far to the center 

 of the spindle. Sometimes it is completely sur- 

 rounded by the others and sometimes merely one 

 end is at the center of the spindle. It is never 

 the bent chromosome but is always one of the 

 larger ones of the group of nine. 



5. In the early prophases is always a mass of 

 chromatin which never takes on the reticular con- 

 dition, but has a more compact consistency and 

 stains more intensely than the remainder of the 

 chromatin material. 



6. At the beginning of the growth period the 

 nucleus becomes large, and some of the chromatin 

 takes on the reticular condition and stains lightly, 

 but there is one mass that is compact, stains in- 

 tensely and has the appearance of a nucleolus. It 

 forms the accessory chromosome. 



7. In synizesis there is no polarization of the 

 chromatin thread. 



8. In the primary spermatocyte are always six 



dumb-bell-shaped chromosomes but two are much 

 larger than the others. 



9. The first spermatocyte division is always a 

 cross division. The accessory chromosome always 

 lies near the periphery of the spindle and passes 

 to one pole undivided much in advance of the 

 others. 



10. All the chromosomes divide in the second 

 spermatocyte division. 



Synapsis and the Individuality of the Chromo- 

 somes: T>. H. Weneich. 



In attempting to determine whether synapsis in 

 this Acridid grasshopper is end-to-end (telosynap- 

 sis) or side-by-side (parasynapsis), it was found 

 that the only method by which conclusive evidence 

 could be obtained was that of following the his- 

 tory of individual chromosomes. 



Of the 12 haploid chromosomes present in this 

 species, at least three were found to possess indi- 

 vidual peculiarities by which they could be recog- 

 nized throughout the growth period and the pro- 

 phases of the first maturation division. 



Parallel conjugation of the fine spireme threads 

 of the early growth stages appeared to occur as a 

 general rule, and different steps in the process 

 could be followed for at least one of the differen- 

 tial chromosomes. Conjugation did not result in 

 loss of identity of the uniting threads in the sense 

 of forming ' ' mixochromosomes, ' ' for the plane 

 of separation between them remained visible 

 throughout the spireme stages. However, pairs of 

 granules often appeared to be fused into single 

 ones. Spireme segments separate out as rods or 

 loops with a single split, tetrads being formed by 

 a second longitudinal split at right angles to the 

 one already present. 



Analysis of the spireme stages of one of the 

 differential chromosomes revealed a seriation of 

 granules (chromosomes) along its length, such that 

 the relative size and position of the granules were 

 constant not only in the cells of one individual, 

 but in those of all the animals studied. 



Chromosomes with peculiarities analogous to 

 those found in the first spermatocyte could be 

 recognized in the spermatogonia. 



In the first maturation division the monosome 

 passes to one pole undivided. The tetrads appear 

 to divide equationally with one exception. In 

 this tetrad the conjugants are very unequal and 

 division is as often reductional as equational. 

 When dividing reductionally the unequal dyads 

 show, with reference to the monosome, a distri- 

 bution according to the law of chance (Mendel's 

 law). 



