CORALLINA. -219 



believe them to be, coloured like the coralline itself. After 

 they have escaped naturally, the tubercles exhibit a small open- 

 ing on their top and become hollow. I have in vain sought for 

 these seminiferous capsules in the winter months. 



The Corallina officinalis, after death, or after being detached 

 and cast on shore, speedily loses its claret colour, fades to a pale 

 pink, and in a few days becomes entirely white. These changes 

 take place with greater rapidity when the specimen is immersed 

 in fresh water, for then the depth of its colour becomes almost 

 instantly weakened. It retains the colour unchanged, on the 

 contrary, in a weak acid, which, however, soon removes the cal- 

 careous crust, and then the specimen bears a close resemblance 

 to some of the articulated Fuci. When the coralline is now ex- 

 amined, it is found that the form and integrity of the specimen 

 have remained unaltered. The axis exhibits the same articu- 

 lated appearance as the crust had done, but the joints are merely 

 constrictions in its calibre, deprived of the colouring matter of 

 the internodes, and do not interrupt its continuity. These stric- 

 tured portions are decidedly fibrous, the fibres parallel and nu- 

 merous, but which become obscure or lose themselves in the in- 

 ternodes. These may be also fibrous, but the structure is not 

 easily made out. Under a magnifier, they appear to be solid, 

 and to be composed of cells exhibiting an areolar or netted struc- 

 ture, the interstices filled more or less with^minute granules, and 

 a set of vessels runs through it, anastomosing on the apices of 

 the extreme joints. This stnicture is best seen when the spe- 

 cimen has been allowed to dry on a plate of glass ; but it must 

 be confessed that the appearances are by no means uniform. 

 The figure which I have given in PI. XXII. Fig. 6, represents 

 very exactly what was seen in one carefully prepared specimen. 

 " When a small living branch of the Corallina officinalis is 

 placed under the microscope with sea-water, wo observe the 

 rounded extremity of each of the last digitations tipt with a thin 



