430 APPENDIX 



AMOEBOID. Usually applied to the flowing movements of a cell, as 



in the Protozoon, Amoeba. 

 AMPHIMIXIS. The mingling of the germ plasm of two gametes in the 



zygote. 

 ANABOLISM. The constructive phase of metabolism. See Katabo- 



lism. 

 ANAEROBE. An organism not requiring free oxygen; e.g., certain 



Bacteria and parasitic Worms. See Aerobe. 

 ANALOGY. Structural resemblance due to similarity of function. 



See Homology. 



ANAPHASE. Period in mitosis during which the daughter chromo- 

 somes move toward the respective centrosomes. See Telophase. 

 ANATOMY. The structure of organisms, especially as revealed by 



dissection. 

 ANTHER. The part of the stamen which contains the pollen sacs 



(microsporangia) in Flowering Plants. 

 ANTHERIDIUM. The organ in plants, such as the Mosses and Ferns, 



in which the male gametes arise. 

 ANUS. Terminal orifice of the alimentary canal. Opening of the 



large intestine either on the surface of the body (Man) or into 



the cloaca (Frog). 

 AORTA. A great trunk artery carrying blood away from the heart. 



See Dorsal Aorta. 

 AORTIC ARCHES. Arteries arising from the ventral aorta and 



supplying the gills in aquatic Vertebrates. Undergo many 



modifications in the ascending series of air-breathing Vertebrates. 

 APHIDS. Small sucking Insects; e.g., the green 'Plant Lice' of 



garden shrubs. 

 ARCHEGONIUM. The organ in plants, such as the Mosses and Ferns, 



in which the female gamete (egg) arises. 

 ARTHROPODA. Phylum of Invertebrates. Includes the Crustacea, 



Insecta, Arachnida, etc. 



ASTER. Radiations surrounding the centrosome during cell divi- 

 sion. 

 ATAVISM. Appearance of grandparental characters in an individual. 



See Reversion. 



