PLUMATELLID^E : PLUMATELLA. 



401 



On each of the two parallel faces we distinguish a shield, a little 

 convex, and of the same shape as the egg itself, surrounded with a 

 rim oi the same colour and consistence. (Fig. 74, a.) In drying, 



Fig. 74. 



.^^. 

 I 



these two faces approximate and become concave, while the rim 

 remains unaltered. A section perpendicular to the two faces shews 

 that the rim has no communication with the shield (Fig. 74, 6) ; 

 that it is distended with a cellular tissue of the same substance as 

 the parietes ; and that the shield encloses, under a shell of the same 

 nature as the rim, a glutinous cellular tissue, the cells of which are 

 filled with transparent, apparently amylaceous, granules, spread in 

 myriads over the object-glass when the perispenn is torn. The most 

 minute observation has been employ- Fig. 75. 



ed without success in finding any 

 indication of an organ analogous to 

 the embryo. 



By a section parallel to the two 

 faces, the difference which exists 

 between the structure of the rim 

 and shield is made apparent. Of 

 the former, the coat, deprived of 

 the tissue which it contains, is 

 seen to be transparent, and divided 

 into cellules arranged in rays which 

 point towards the centre of the organ; 

 while the resinous and woody thick- 

 ness of the shield presents a great 

 number of small globular yellowish 



