364 GLOSSARY 



contradistinction to the craniate Chordates which make 

 up the bulk of the vertebrates. 



Angio sperms : The higher plants, which have their seeds' 

 enclosed in seed-vessels. 



Anthropoid Apes: Apes of the family Simiid^, which 

 approach man most closely in their organization, namely, 

 the chimpanzee, the gorilla, the gibbon, and orang-utan. 



Antibody: Chemical substances produced in the blood in 

 reaction to the injection of antigens' or toxic substances 

 and capable of counteracting or neutralizing said sub- 

 stance. Such antibodies are specific for determinate 

 antigens. 



Antigen: Any substance that causes the production of 

 special antibodies in the blood of susceptible animals, 

 after one or several injections. 



Arthropods: The phylum of exoskeletal invertebrates com- 

 prising crustaceans, arachnida, insects, etc. 



Atavism: The resemblance to an ancestor more distant than 

 the parents. 



Automatism: A spontaneous action, not in response to 

 recognizable stimuli. 



Basichromatin: That portion of a cell's nuclear network 



which contains nuclein and is deeply stained by basic dyes. 

 Biparental: Derived from two progenitors, i.e., a father and 



mother. 

 Brachiopods: Invertebrate animals bearing a superficial 



resemblance to bivalve molluscs, but belonging to a totally 



different group — lamp shells. 



Cambrian: The "oldest" system of the Palaeozoic group of 

 fossiliferous rocks. 



Carbohydrates: The sugars', starches, etc., — polyhydric 

 alcohols with aldehydic or ketonic groups, and acetals of 

 same, etc. 



Catalyst: A substance which accelerates a chemical re- 

 action without permanently participating in it, being 

 left over unchanged at the end of the process. 



Centriole: The centrioles or central bodies are the foci of 



