AUTHOR’S ABSTRACT OF THIS PAPER ISSUED 
BY THE BIBLIOGRAPHIC SERVICE, FEBRUARY 24 
STUDIES IN THE DEVELOPMENT OF THE OPOSSUM 
DIDELPHYS VIRGINIANA L. 
III. DESCRIPTION OF NEW MATERIAL ON MATURATION, CLEAVAGE 
AND ENTODERM FORMATION 
IV. THE BILAMINAR BLASTOCYST 
CARL G. HARTMAN 
The Wistar Institute of Anatomy and Biology and the University of Texas 
CONTENTS 
PART III. DESCRIPTION OF NEW MATERIAL ON MATURATION, CLEAVAGE, AND 
ENTODERM FORMATION 
Er OC WE ENO Mixers: S50. |: Sta Ee Os Ca Re POS RR ye ES Ce aes 
Gee TeravOny LEMALKS terest reer oe, so PIER oicmerceners Goo aire eked nicl ce oe 
(Sy lB GST rrope Oren Moe tian PeWA tmietonr lorie Aare met icics Gibt Uaemne Eon aera Riche, cictovc sak Scola ame eee 
Cu Viatenralvanditechmiquessseesnc..: poor secrete rite a ree a 
d. External changes in the female opossum at ovulation 
Maturation and cleavage to the formation of the blastocyst................ 
See AEN PERO MALI AMY COD emvatiane tac jac elect Me cP ceo oinpetn eases oi ROME: 
eheb uly slain’. ifn abl sate sac we tecve Sasa 2 Sepa ten aia weer sictansese «ptt 
CaphheryouneMberin ese resis ew eater oa se Mn ee, ceases, ES eee 
edtheshirsty Clea aoe e ciens hey ected See eae teks renee arene exch ccna aks: sepa oe 
en hersecondsclea Varese seme varus Metneh san Vif nepal deh auc gti ne Senet 
f. On the origin of the crossed arrangement of the first four blastomeres. . 
g. Comparison of the 4-celled egg of the opossum and of Dasyurus...... 
h;. Deutoplasmolysis‘or the elimination of yolk. .2 3.5.22. 6 ee 2 olan 
i. Later cleavage to the formation of the blastocyst..................... 
j2.On the: fate omthe timstrtwo blastomenress ess. cis os. ce nc nel ene ore 
The formation of the entoderm 
SAG ENE Lr alliak bases yay aera Me Pe ted revere i hat LR ES ee lia sc Sg ARS etn oh aN 
a bhe youngest unilamnar! pla sbocysiseyact cas cee x: -/ «evoke cle olotele en epee 
Pebhe rst ENCOGSLIN MAG UME EGOS 8st oho cusehe cca sjeus' x cas) sameeren urchaebdle 
. The detachment of the entoderm mother cells.......................:: 
. The proliferation of entoderm confined to one pole of the egg......... 
AeA CRO LM CAL Alc Creer am ey Meee eth: eer d tes 5 ctenc) ah = ,ere.chsuoieted epee os accchs keys 
. Included: cells which may not be entodermal........ . cece vo csao >= 
Hurthenpolanrrdiienrentiatlones ya. a. ei 4ci- <ccias clteteite teksts =) orto 
, Thetemtbnyonte ares, supenicial in postion... ..-.....” sameprmeh acca ee 
1 
= Doo po Qo» 
