GLOSSARY 241 



'YTOPLASM. The protoplasm of the cell apart from that of the nucleus; the 



cell body. 

 DENDRITES. The protoplasmic branching processes of a nerve cell. 



_ DIASTASE. A ferment which transforms starch into sugar. 



^DIFFERENTIATION. The evolutionary process or result by which originally 

 indifferent parts or organs become changed or specialized in either 

 form or function; specialization. 

 DIPLOID. Refers, in connection with chromosomes, to the double or normal 



number, half from the male, half from the female parent. 

 DISSEPIMENT. A septum or partition between the somites of annelids. 

 - DOMINANT CHARACTER. A character inherited from one parent which de- 

 velops, while the factor for the same character from the other parent 

 remains latent or undeveloped (recessive). 



ECDYSIS. Moulting, or the act of shedding an outer coat or integument. 

 ECTOBLAST. The outer primary cell layer in the embryo of any metazoan 



animal; the ectoderm. 

 ECTODERM. The completed outer layer of cells in all metazoan animals, 



formed by the cells of the ectoblast. 



ECTOPLASM. The outermost recognizable living substance of a cell. 

 ENCYSTMENT. The process of forming a tough resistant covering or cyst 



within which the organism remains alive. 



ENDODERM. The inner layer of cells surrounding the enteron in all metazoa. 

 ENDOENZYME. A ferment formed, and normally acting, within the proto- 

 plasm of a cell. 



ENDOMIXIS. Asexual re-organization of the cell (Protozoa). 

 .ENDOPLASM. The inner protoplasm of a protozoan cell. 

 ENDOPODITE. The inner one of the two main divisions of the typical 



limb of a crustacean. 



ENDOTHELIUM. Superficial layer of cells derived from the mesoderm. 

 ENTERON. The intestine, alimentary canal, or digestive space which 



is primitively derived from the endoderm. 

 . EPIDERMIS. The non-vascular outer layer of the body. 

 EPISPORE. The outer covering of a spore. 

 EPITHELIUM. Any superficial layer of cells of mucous membranes including 



the proper secreting tissues of glands, etc. 

 EXOPODITE. The outer one of the two main divisions of the typical limb 



of a crustacean. 



FACTOR. A specific cause in a germ cell of a developed character. 

 /"FAECES. Excrement voided from the anus; "castings." 

 FERMENT. A chemical substance which stimulates chemical activity in 



other substances. 

 FERMENTATION. A chemical change produced in an organic substance by 



the activity of ferments usually derived from living things. 

 GAMETE. A reproductive germ cell, male or female. 

 GAMETOPHYTE. The sexual generation of a plant. 



3LION. An aggregate of nerve cells, nerve fibers, and supporting cells. 

 GASTRULA. A stage in development in which the embryo consists of two 

 germ layers enclosing the archenteron. 



