Anatomy of the Corallina opuntia. 2^3 



means of acids. The deposition of lime begins with the very 

 first appearance of the branches, the minutest stalks of the Cor. 

 opuntia were found to contain some lime, the quantity of 

 which increased as the branches grew. 



Cavolini observed on the surface of corallines minute fibres 

 filled with granular bodies, which he took for seeds. They 

 were likewise seen by Olivi, who thence inferred that they came 

 chiefly from the joints. It is evident, however, that they are on- 

 ly filaments of confervae, the ends of which are often covered, 

 and imbedded in the substance of the coralline, and they fre- 

 quently remain attached to it, even after the lime has been re- 

 moved by acids. Lamouroux likewise observed these filaments, 

 and found them capable of spontaneous motion. The latter ob- 

 servation reminds us of a similar fact mentioned by Covalini, 

 who observed the Sertulariajastigiata, covered with filaments 

 which possessed spontaneous motion. In specimens of the Cor. 

 opuntia^ which Schweigger had preserved in spirits, he discover- 

 ed similar filaments, which he had looked for in vain in those 

 recent from the sea. They appeared under the microscope like 

 tubes interrupted by small knots. The knots, however, on apply- 

 ing higher magnifying powers, were found to be tranverse parti- 

 tions, lying parallel to each other at short distances': the fila- 

 ments had altogether the appearance of confervae. Should thev 

 be regarded as such, there is nothing remarkable in their 

 spontaneous motions, since similar motions have often been 

 seen in confervae, and are described by Vaucher and other wri- 

 ters. The mere resemblance, however, is not conclusive as to 

 th(pir being distinct confervae, since they have likewise the clos- 

 est resemblance to the filaments within the coralline. They are 

 probably continuations of the inner substance, like those pro- 

 jecting from the Cellaria cereoides, upper roots, (liiftwurzeh, 

 air-roots), appearances presented hy confervae ; and the whole 

 coralline consists of cells and conferva-filaments. Ellis observ- 

 ed in the substance of corallines minute vesicles which he sup- 

 posed to be air-vesicles, destined to preserve the coralline erect 

 in the water. They were likewise seen by Lamouroux ; but as 

 he frequently observed round bodies in them, he considered 

 them ovaria. From the foregoing account of the structure of 

 the corallines, there can scarcely be a doubt that these vesicles 



