PROTOPHYTKS. 



motion; twenty-four around the edges of the transparent case, and eight projecting 

 from the central parts, and, by their combined action, the cluster, enclosed in its 

 delicate envelope, proceeds as one body. Each of the constituent individuals of a 

 cluster is, of itself, a perfect organism, possessing a motion of its own ; yet, when 

 united with fifteen others, all act in concert. 



THE REVOLVING GLOBE, OR YOLVOX. About 150 years ago, Leuwenhoeck 

 discovered in water a singular hollow globe, studded with green specks, which 

 advanced through the fluid with a rolling motion. It was at first supposed that 

 the globe was a single animal, but the microscopists of the present day have shown 

 now the true nature of this structure. The little green specks that gem the surface 

 are protophy tes ; each being a perfect monad, furnished with two cilia, and pos- 

 sessing a bright-red eye-speck. They are all connected together, and every individ- 

 ual is attached to those immediately adjacent by delicate fibres, varying in num- 

 ber from three to six. The thousands thus embedded throughout the entire surface 

 of the transparent spherical shell, form the hollow globe, and bear to it the same 

 relation as the monads of the breastplate cluster to their pellucid case. The whole 

 globe bristles with the cilia of the individual monads ; and, by the united action of 

 these slender organs, rolls through the water with the same part always foremost; 

 when the fluid is colored the current and eddies produced by the cilia are clearly 

 detected. This change of place seems necessary for the support of the numerous 

 groups, which range continually in their rolling globe, through new regions of 

 space abounding with matter adapted to their development and increase. 

 In figure 14 the revolving globe is faithfully 

 delineated. The minute dots with which it is 

 covered are the monads that compose it, and 

 the interlacing net-work are the filaments 

 which connect them with each other. The 

 direction of the globe in its progress is indi- 

 cated by the arrows, and the cilia that propel 

 it are distinctly discerned fringing its surface. 

 Within the globe a number of smaller globes 

 are perceived ; and these lead us to consider 

 the extraordinary manner in which these 

 curious groups are multi plied. They increase 

 by a voluntary separation : from time to time 

 new spherical clusters are thrown off from the 

 original globe ; not, however, from its outer 

 surface into the surrounding water, but from 

 the inner surface into the space enclosed by the 

 transparent shell. Six or eight of these spherical groups are usually found within 

 the parent globe; though, at times, as many as twenty have been seen at once, 

 with their forms well defined, and their color of a bright green. Openings exist, 

 both in the primary sphere and in the interior globes, through which water passes 

 and repasses for the purpose of affording nourishment to these vegetable forms. As 

 the young globes increase in size, the surrounding envelope expands, and as soon 

 as they have attained a certain degree of maturity, it bursts asunder and permits 

 them to escape. Now, uncontrolled in their motions, they range through a wider 



