THE MENDELIAN RATIO IN RELATION TO CERTAIN 
ORTHOPTERAN CHROMOSOMES 
EK. ELEANOR CAROTHERS 
SIXTY-NINE FIGURES 
CONTENTS 
SUMAN NE LONE Cd CeO ik dig wink vss anids dade ¢athinag senna 487 
aN ev EM Bk Sg Seid 5 ud a WG 3 aS csala welts declan ee 489 
Se RE Tee O STING ee Fe A Pm 2 Sha sa iaildle 6 bf aia yas call auinca ola goes Oe 489 
2, Growth period and earlier diffuse stages...... 6.0! ... od... .0.--.e0es0, ee 489 
yy UMD SUR p20 ee ck | 492 
AM CMM AUIEUMA EOC YLES 0.) o)2 02m. deci fig dow win ae ta ss oe a uisad vale OR ae 496 
ee ITS Ws Ne nn Sl es cee ca send edau eis, 2 eget a ee 497 
Sana OCIS OMSPIV ARONA: F 5... 5.2.5. os bas cals ah sdeleg cacy ca Oth yaa Oe 498 
UEURETSEOT o. sa eS EE he US er rn mre ark UT 498 
NAAT SOE rE OWE eI PS a sys as ow ia ward diay bay widienn hee ea 504 
INTRODUCTION 
The aim of this paper is to describe the behavior of an unequal 
tetrad which occurs in the first spermatocytes of three members 
of the Oedipodinae: Brachystola magna, Arphia simplex and 
Dissosteira carolina. The distribution of the dyads of this tetrad, 
in relation to the accessory, follows the law of chance; and, there- 
fore, affords direct cytological support of Mendel’s laws. This 
distribution is easily traced on account of a very distinct differ- 
ence in size of the dyads. Thus another link is added to the 
already long chain of evidence that the chromosomes are distinct 
morphological individuals continuous from generation to genera- 
tion, and, as such, are the bearers of the hereditary qualities. 
McClung wrote (’05, p. 303), ‘‘In the absence, therefore, of defi- 
nite knowledge of the chromosomes in the germ cells of organisms 
exhibiting Mendelian characters or mutations we are warranted 
~ in supposing them to be of the same general character as the ones 
487 
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