GLOSSARY. 



ACETABULA. Lat. acetabuluiii, a little vessel. Sucking discs as on the tentacles 



of Physalia. 



AOETA. Gr. The chief artery. 

 CEPHALOTHORAX. Gr. kephale, head; thorax, chest. The anterior division of 



the body in Crustacea and Arachnida, composed of the amalgamated 



segments of the head and thorax. 

 CILIA. Lat. cilium, an eyelash. Microscopic filaments having the power of 



vibratory movement. 

 CffiNOSARC. Gr. Koinos, common ; sarx, flesh. The common stem uniting the 



separate animals of compound hydrozoa, &c. 

 CORPUSCLE. Lat. corpusculum, a little body. Small coloured bodies, as in the 



endoderm of hydra, p. 59. 

 DIFFERENTIATED. Modified into definite organs, or parts ; as distinct from 



structureless protoplasm. 

 ECTODERM. Gr. ektos, outside, derma, skin. The internal layer or skin of the 



Ccelenterata. 

 EFFERENT. Lat. effero, to carry out. A vessel which carries fluids out of the 



body is said to be efferent. 

 ENDODERM. Gr. endon, within, derma, skin. The inner layer or skin of 



Coelenterata. See ECTODERM. 



ENDOSARC. Gr. endon, within, sarx, flesh. The inner layer of sponges. 

 EPIDERMAL. Gr. epi, upon ; derma, skin. Eelating to the outer layer of skin. 



As applied to colour, surface pigment as distinct from hypodermal, or 



deep-seated colour. 

 GASTROVASCULAR CANAL. Gr. gaster, belly, Lat. vasculum, a little vessel. The 



canals or vessels in the umbrella (manubrium) of hydrozoa. 

 GONIDIA. Gr. gonos, offspring; oidos, like. Reproductive bodies in Sea- 

 anemones. 

 HTDRANTH. Gr. hudor, water ; anthos, flower. The bodies or polypes of 



hydroids which exercise nutritive functions. They were called polypites 



by Huxley. 

 HYDROPHTLLIA. Gr. hudor and phyllon, a leaf. Leaf -like organs protecting the 



polypites of hydrozoa. 



HYDROSOMA.. Gr. hudor and soma, body. The entire organism of a hydrozoon, 

 HYPODERMAL. Gr. hypo, beneath ; derma, skin. In colour, such as lies beneath 



the surface, as distinct from epidermal. 



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