GLOSSARY 167 



crop. The pouch-like enlargement of the digestive tube 

 used to store food. 



cuticle. The outer skin. In protozoa the cell wall. 



cytology. The science of cell structure and function. 



cytoplasm. The protoplasm of the cell proper, as con- 

 trasted with the nucleoplasm, or protoplasm of the 

 nucleus. 



D 



desmid. ) _ 



Y Minute unicellular algse. 



digit. A terminal division of an appendage of vertebrates, 



finger or toe. 

 distal. Away from the point of attachment, opposed to 



proximal, 

 dorsal. The back or upper surface. 



E 



ectoderm. The outermost layer of cells. 



ectoplasm. The outer, denser protoplasm in protozoa. 



embryo. The young of an animal before its parts are fully 

 developed, and before the commencement of inde- 

 pendent existence. 



embryology. The science of the development of animals 

 and plants. 



encyst. To enclose in a cyst or case, common in protozoa 

 and bacteria for protection. 



endopodite. In Crustacea the branch of a biramous append- 

 age toward the median line of me body. 



enteron. The digestive tube, especially the simple tract 

 of lower animals. 



entoderm. The inner tissue lining the enteron or digestive 

 tube. 



