224 



REPORT ON THE STATE CABINET. 



and they sometimes remain in contact throughout their entire length ; 

 but in the greater number of species, there is a small portion of each 

 one free on one side towards the aperture. This character is shown in 

 numerous examples (Plates i, ii and iii).* 



In some forms the cellules are contiguous in their lower portions, while 

 the entire upper or outer part becomes free, as seen in G. ditonensis 

 (Plate i, figs. 1, 2 and 3); while in one of the bi-celluliferous species from 

 Iowa, the cellules are distinct from each other at their origin, and the 

 upper extremity of one scarcely reaches to the base of the next in 

 advance (Plate ii, fig. 10), and they are therefore not properly in contact 

 in any part of their length. The same is more emphatically true of 

 Rastrites where there is a large interval between the bases of the 

 cellules, which are often nearly rectangular to the axis. 



The earlier or first developed cellules are always smaller than those 

 following, and they reach their full development at different distances 

 from the base or axil, in different species. Towards the distal extremi- 

 ties the cellules usually become gradually smaller, to the last one, while 

 sometimes they become abruptly less and less ; the latter feature probably 

 occurring in young and vigorous growing individuals, while the gradual 

 diminution is apparently characteristic of an approach to maturity. 



Although we regard the cellule as limited by the cell-partitions, yet 

 in well-preserved specimens there is sometimes a swelling of the test of 

 the common body below the cellule, indicating an enlargement of the 

 parts at the bases of the polypites. In one species there is an evident 



* The mode of budding and the form and arrangement of the cellules in the Sertularians are 

 shown in the accompanying figures of two species of Sertulaeia (figs 1 and 2) from our own 

 coast. Fig. 3, with a range of cellules on one side only, is a Plumularia. 



Fig. 1. 



Fig. 3. 



Fig. 2. 



