AND EXPLANATION OF TERMS. 5 



perpendicular muscular PARTITIONS (septa), all of which are 

 inserted into the column- wall, but advance into the cavity 

 in various degrees. Some are inserted by their inner edge 

 into the stomach-wall, completely dividing-off the cavity : 

 these maybe called primary septa (septa primordialia) . 

 Others are placed intermediately between these, which do 

 not reach the stomach-wall; these are secondary septa 

 (s. secundaria). Others, again, are intermediate between 

 these and the former, whose height is still lower (these may 

 be distinguished as tertiary (s. tertiaria) ; and so on, if 

 there be any series beyond this. The spaces thus parted 

 off in the cavity, I would call intersepts (inter -septa) . 

 The free edges of the secondary and tertiary septa, and also 

 of the primary ones below the stomach, carry a thin 

 membrane which encloses the ovaries (ovaria), and is 

 terminated by a sort of CORD (craspedum), much twisted 

 and involved. Long missile CORDS (acontia) are in some 

 species attached by one end to the partitions, and lie coiled- 

 up, or float freely, in the intersepts : these are, by the volun- 

 tary contractions of the animal, forcibly ejected through the 

 loop-holes, into which they are then gradually withdrawn. 

 Both the craspeda and the acontia are almost wholly com- 

 posed of thread-capsules (cnidce), which contain a coiled 

 wire (ecthoraium). This wire is shot out under particular 

 stimulus, and is an efficient weapon of offence ; it is usually 

 surrounded with one or more spiral bands composing the 

 SCREW (strebla), each of which carries a series of barbs 

 (pterygia) ; and the whole apparatus is a vehicle for the 

 infusion of some highly venomous fluid. 



The different conditions assumed by the animal, may be 

 distinguished as the FLOWER (antfais), when the disk with 

 its tentacles is expanded ; the BUTTON (oncus) , when these 

 are retracted and concealed by the closing over them of the 

 summit of the column. 



