GLOSSARY 237 



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. 



ENDOPLASM. The inner protoplasm of a protozoan cell. 



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

 limb of a crustacean. 



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

 is primitively derived from the endoderm. 



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



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. 



RECES. 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. 



FIBRO-VASCULAR BUNDLE. An aggregate of woody fibers, cellular ducts 

 and columnar cells found in vascular cryptogams and higher plants. 



GAMETE. A reproductive germ cell, male or female. 



GANGLION. 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. 



GASTRULATION. The process of gastrula formation. 



GEMMATION. Asexual reproduction by budding. 



GENETICS. The science of heredity. 



GERM PLASM. The reproductive protoplasm distinguished from the so- 

 matic or organ-forming protoplasm of the individual. 



GONAD. A reproductive organ in which the germ cells are formed. 



HAEMOCOEL. A body cavity containing blood, and different from a coelom. 



HAPLOID. Refers, in connection with chromosomes, to the half number 

 subsequent to reduction. 



HEPATO-PANCREAS. The digestive gland of the Crustacea. 



HEREDITY. The appearance in offspring of characters the factors for which 

 are in the germ cells. 



