336 Glossary 



BLAS'TO-DER'-MIC VES'-I-CLE. A hollow sphere, formed from the segmented 

 egg of a mammal, which becomes attached to or embedded within the 

 wall of the uterus. 



BLAS'-TO-PORE. The mouth of a gastrula. 



BLAS'-TU-LA. A mass of cells, usually in the shape of a hollow sphere, 

 formed by repeated divisions (cleavages) of an egg. 



BLENDING INHERITANCE. iGalton's term for that kind of inheritance in 

 which the characters of the parents seem to blend in the offspring. 



BRACH-Y-DAC'-TY-LISM. The condition of having abnormally short fingers 

 or toes. 



CELL. The fundamental unit of structure and function in all living things. 



CEN'-TRO-SOME. The body at the center of radiations in a dividing cell. 



CEPH'-A-LO-PODS. A class of mollusks which includes the squid, cuttle- 

 fish and devil-fish. 



CER'-E-BRAL GANG'-LI-ON. The brain of an invertebrate animal. 



CHARACTER. Any feature or property of an organism. 



CHOR'-DA. A cellular rod in vertebrate embryos which forms the basis of 

 the backbone. 



CHOR'-DATE. A member of the highest phylum of the animal kingdom, 

 including all animals having a chorda or backbone. 



CHO'-RI-ON. A tough membrane around an egg secreted by surrounding 

 cells. 



CHRO'-MA-TIN. The deeply staining substance of the nucleus. 



CHRO'-MO-MERES. The linear series of chromatin bodies in a chromosome. 



CHRO'-MO-SOMES. Deeply staining bodies found in the nucleus at the 

 time of indirect division. 



CHROMOSOMAL VESICLES. The swollen chromosomes of inter-division 

 stages. 



CIL'-I-A. Minute protoplasmic threads on the surface of a cell which pro- 

 duce movements in the surrounding medium by waving back and 

 forth. 



CLASS. The chief sub-division of a phylum. 



CLEAV'-AGE. The division of the egg cell into many cells after fertilization. 



CLEP-SI'-NE. A genus of leeches. 



COE'-LOM. The body cavity. 



CONTINUOUS VARIATION. A series of minute variations. 



CORRELATIVE DIFFERENTIATION. Differentiation due chiefly to the interac- 

 tion of different parts of an organism. 



CRE-PID'-U-LA. A genus of marine gastropods. 



"CRISS-CROSS" INHERITANCE. Morgan's term for that kind of inheritance 

 in which .maternal characters are transmitted to sons and paternal 

 ones to daughters. 



