Desm'lihcfP.'] INFrSORT.VL ANTMALrri.F.S. 231. 



original segments are piished fiirtlier asunder, and at length are 

 disconnected, each taking with it a new segment, to sui)ply the place 

 of that from which it has separated." 



"It is curious to trace the development of the new portions. 

 At first they are devoid of colour, and have much the appearance of 

 condensed gelatine, but as they increase in size, the internal fluid 

 acquii-es a green tint, at first very faint, but soon becoming darker ; 

 at length it assumes a granidar state. At the same time the new segments 

 increase in size, and obtain their normal figuj'e ; the covering in some 

 species shows the presence of puncta or granules ; and lastly, in 

 Xanthidium and Staurastn'um, the spines and processes make their 

 appearance, beginning as mere tubercles, and then lengthening until 

 they attain their perfect form and size ; but complete separation often 

 occurs before the whole procees is completed. This singular process 

 is repeated again and again, so that the older segments are united 

 successively, as it were, with many generations. In SjjJiarozosma the 

 same changes take place, but the cells continue linked together, and 

 a filament is formed, which elongates more and more rapidly as the 

 joints increase in number. This continued multiplication has its 

 limits ; the segments gradually enlarge whilst they divide, and at 

 length the plant ceases to grow, the division of the cell is no longer 

 repeated ; the internal matter changes its appearance, increases in 

 density, and contains starch granules, which soon become numerous; 

 the reproductive granules are perfected, and the individual perishes. 

 In a filament the two oldest segments are found at its opposite 

 extremities; for so long as the joints di'vo.de they are necessarily 

 separated further and further from each other. Whilst this process 

 is in progress the filament in Sjjharozosma, consists of segments of 

 all sizes ; but after it has reached maturity there is little inequality 

 between them, except in some of the last formed segments which 

 are permanently smaller. The case is the same with those genera, 

 in which the separation of the cells is complete. It is obvious that, 

 from the beginning, the new segment must have the same breadth 

 as the junction from which it springs ; and when consequently, the 

 junction is as broad as the cell, — /. e. where the valves are united by 

 their entire breadth, the new portion is of equal width, and so can 

 be distinguished only by other means than their size." 



