GLOSSARY. 187 



Digitate (Lat. digitus, a finger) When a part supports 

 processes like fingers. 



Entomostraca (Gr. entoma, insects ; ostracon, a shell) 

 The order of small Crustaceans, many of which are 

 inclosed in an integument like a bivalve shell. 



Exuvium (from the Latin signifying the skin of a ser- 

 pent) The skin which is shed in moulting. 



Fucivorus (Lat. fucus, sea-weed ; and voro, I devour) 



Animals which subsist on sea-weed. 

 Frond (Lat. frons, a leaf) A term applied to that part 



of floweiiess plants resembling true leaves. 



Gasteropoda (Gr. (/aster, stomach ; pons, a foot) That 

 class of molluscous animals which have the loco- 

 motive organ attached to the under part of the body. 



Hinge That part of a shell at which the valves cohere. 



Ligament A membrane close by the hinge which con- 

 nects the valves. 



Mantle The external soft, contractile skin of the mol- 



lusca, which covers the viscera and a great part of 



the body like a cloak. 

 Medusce A genus or family of soft radiated animals, or 



Acalephse, so called because their organs of motion 



and prehension are spread out like the snaky hair 



of the fabulous Medusa. 

 Multivalve (Lat. multus, many ; valvce, folding doors) 



Shells composed of many pieces or valves, as the 



Chiton. 



Nudibranchiate (Lat. nudus, naked; branckice, gills) An 

 order of Gasteropods in which the gills are exposed. 



