Tank, Earth 



A structure made by an excavation and an earthen dam 

 across a drainage course for the purpose of impounding 

 drinking water for livestock. 



Tapeworm 



A flatworm in class Cestoda, phylum Platyhelminthes, 

 parasitic in the adult stage in the intestines of Vertebrates. 



Taproot System 



A root system in plants characterized by a large primary 

 root (the taproot) that extends deep into the soil and has 

 many smaller branches, e. g. alfalfa, cf. Fibrous root system. 



Tarn 



A small lake or pool in the mountains. 



Taungya 



An area cleared of vegetation and undergoing Secondary 

 Succession in Burma. 



Taxis 



Movement of an organism directly towards or away from 

 a stimulus, e. g. Phototaxis, (q. v.) 



Taxocline 



A series of gradations in taxonomic status of organisms 

 in which hybridization is involved. 



Taxon 



Any taxonomic category, e. g., species, genus, variety. 



Taxonomy 



The science of classification of organisms; the arrange- 

 ment of organisms into systematic groupings such as Species, 

 Genus, Family, and Order, cf. Systematics. 



Tectonic 



Refers to processes that cause the formation of features 

 of the earth's crust, e. g., upwarping. cf. Isostasy. 



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