f 



486 Miscellaneous. 



glomeruli the exoderm of the stolon is rapidly modifiod. Instead 

 of being very thin and flattened, it becomes cylindrical. The 

 nuclei are usually on the internal face. The reserve material, in 

 the form of white opaque granules, and staining with carmine, is 

 arranged, on the contrary, on the external face. The reserve 

 granules are essentially different from excreted pigments, white or 

 yellow, which form the ornamental lines on different parts of the 

 bodies of the ClavelincB. In the lumen of the stolon there is found 

 a mass of cellules which ought to be regarded as phagocytes, from 

 the mesenchymatous elements arising without doubt from the meso- 

 derm of the former animals of the colony. Many of these mesen- 

 chymatous cellules also enclose reserve material, always under the 

 form of white granules, occupying in the protoplasm the vacuoles 

 which are generally blended into one large central vacuole ; the 

 protoplasm and the nucleus are thrust out to the periphery. The 

 cellules so modified can agglomerate, and they end by blocking up 

 the greatly distended stolon. Although these cellules appear to 

 multiply actively, we have never been able to observe mitosic 

 figures. The epicardiac partition presents no modification ; it is 

 always very thin and the two leaves remain joined. After a certain 

 time the stolons divide into sections completely isolated one from 

 another ; each new section presents numerous digitations. These 

 various fragments always possess a portion of epicardium. 



Further Evolution of the Sections. — The sections so isolated may 

 remain for a longer or shorter time without evolution, according to 

 the surrounding conditions. The development of the buds first 

 shows itself by the change of aspect of the fragment of epicardium. 

 The epicardial cells proliferate energetically by karyokinesis and 

 become strongly colourable. They soon form a hollow vesicle, com- 

 parable to the internal vesicle of the normal buds of Synascidiaus ; 

 though we have not followed step by step the transformations of 

 the vesicle, we do not doubt the homology of its ulterior develop- 

 ment with that of the ordinary blastozoites of Clavelina. From 

 the beginning of this process there is a rapid disappearance of the 

 reserve material accumulated in the exoderm. The height of the 

 epithelial cells diminishes in proportion as the cells multiply and 

 empty themselves of their reserve material. The reserve material 

 of the mesenchymatous cells disappears equally by digestion proper 

 without the intervention of foreign elements. 



Summary. — A. The reconstitution of the corms of ClaveVuia, after 

 winter, is accomplished by a process of budding homologous with 

 the normal process of budding. 



B. The accumulation of reserves in the form described above is to 

 be met with in the colonies collected in July. It is exaggerated in 

 proportion as the sexual reproduction diminishes (August and 

 September), and attains its maximum in autumn, when the old 

 individuals of the cormus, first reduced to their tunic of cellulose, 

 have finally disappeared. 



C. It ought, then, to be interpreted as a normal physiological 

 arrangement, permitting the latent life of the cormus during a 

 certain time. It is a process of hibernation comparable with that 

 which we have already described in the Polyclinidae.— Coviptes 

 Eendus, 1896, torn, cxxiii. pp. 318-320. 



