/ GENERAL DESCRIPTION 



2. The Column (Columna). 



The body rises in a more or less cylindrical shape, when 

 the base is attached, like the trunk of a tree, often grace- 

 fully and rapidly diminishing from the basal expansion, 

 and sometimes dilating towards the upper extremity : — this 

 I call the column. At the summit (vertex), the column is, 

 as it were, cut off transversely, forming a distinct margin 

 (margo). In some cases, as in Actinoloba, the margin rises 

 into a thickened parapet (tichium) or low wall, separated 

 from the tentacles by a groove or fosse (fossa). In others, 

 there is neither parapet nor fosse. The margin may be 

 notched (crenata) ; or, instead of notches theje may be 

 distinct tentacles, constituting the outer row of these organs; 

 in this case the margin is tentaculate (tentaculata) . 



The surface of the column may be quite SMOOTH (Icevi's) ; 

 studded with low warts, — warty (verrucosa) ; or marked 

 with longitudinal sunken lines, — furrowed (sulcata). 

 When the furrows are deep and the intermediate spaces 

 swell out in a rounded outline, it is invected (invecta) ; 

 when the column is surrounded by transverse wrinkles, it 

 may be called INSECTED (insecta) ; when these insections are 

 so deep as to seem to cut-off or divide the body into parts, 

 it is constricted (constricta) ; when the surface is crossed 

 by numerous longitudinal and transverse wrinkles, it is can- 

 cellated (cancellata) ; when minutely and very irregularly 

 wrinkled, like the bark of a rough tree, it is corrugated 

 (corrugata). Some of these conditions are not permanently 

 characteristic of any species, but are assumed temporarily 

 during the changes of form induced by contraction. As 

 to substance, the column may be tough and resisting, 

 approaching a LEATHERY consistence (coriacea) ; FLESHY 

 (carnosa), when soft but moderately firm ; or pulpy 

 (pulposa), when very soft and yielding. 



