282 Chromosomes in the Spermatogenesis of Anasa Tristis 
way a nucleolus, and is morphologically wholly unlike the same chromo- 
some figured by Wilson at this stage. 
Fourth, that the eleven chromosomes of the first spindle are al/ bival- 
ents and that the eleven chromosomes of the second spindle are all 
univalents. 
Fifth, that in both the first and second spindles one chromosome— 
which we believe to be the eccentric chromosome of the late first prophase 
—often lags in division, but that normally its final division occurs in 
both spindles. 
Professor Wilson in his recent paper in Science, .February, 07, reply- 
ing to our preliminary.note says, that he thinks the contradiction in our 
results is probably due to the difference of method employed, we having 
placed our faith in smear preparations while he has relied on sections. 
We are glad of an opportunity to emphasize this faith, believing that for 
demonstration of the structure and count of chromosomes our modified 
smear preparations are more reliable than sections, and it is for this 
reason we have abandoned the use of sections in studying chromosomes 
except for comparative work and for studying the topographical rela- 
tions of the cells. In cells fixed and sectioned nearly all the delicate 
details shown in the chromosomes of our smear preparations are com- 
pletely lost, and it ought to be too obvious to mention that a method 
which presents clearly each individual chromosome in its integrity offers 
decided advantages when the question of accurate counting assumes the 
importance and develops the contradictions familar in recent literature. 
In spite of Professor Wilson’s maintaining “ that the determination of 
the number of chromosomes in a given species demands more critical 
treatment than the mere matter of counting or photographing,” this 
elementary pursuit of counting chromosomes has certainly played a very 
significant part in recent observations. 
The Eccentric Chromosome, 1. e., Accessory Chromosome, McClung, 
Odd or Heterotropic Chromosome Wilson, 05-06, Monosome Montgom- 
ery, 06. —The three investigators of the spermatogenesis of Anasa tristis 
“As the names given to this chromosome in Anasa are each descriptive of 
the investigators interpretation we were unable to adopt any of them and 
in our preliminary paper we suggested “eccentric”? as a convenient term. 
“The frequent eccentric position of this bivalent chromosome outside the 
characteristic ring arrangement of the chromosomes in the late prophase, 
seems to warrant suggesting “eccentric” chromosome as a convenient 
descriptive name for this special chromosome.” Foot and Strobell, Bio. 
Bull., Vol. XII, 1907. 
