199 



with those in the zooecia mentioned above. Here also an oblique distal wall is 

 found between /S and y, which in the fully developed internode is only repre- 

 sented by a round, single-pored rosette-plate, and in the distal half of the seg- 

 ment ;' is a narrow, oval cryptocyst depression, the bottom of which is perforated 

 by a round pore, equivalent to the transverse slit in the zooecium. In a very 

 young internode (6 v, 6 x) the calcareous wall is still very thin, and the inner 

 segments accordingly of quite a different shape. The distal wall (dw) has here 

 a considerable extent, and the cryptocyst not yet being formed an oval opening 

 is seen in its place in the calcareous wall, covered by a membrane. The distal 

 stem-internode (fig. 6 h), which bears the two main branches, is a transitional 

 form between the stem-internodes and the bifurcate internodes of the main 

 branches, and like these it is divided into two branches, of which however one 

 is very short. The long branch has on its inner side a cryptocyst depression, 

 perforated by a pore like that of the stem-internodes, and the short branch is 

 formed by an a and a /8 springing from 6. Each branch has a single-pored ro- 

 sette-plate, one situated between /? and 6, and the other between /3 and ;'. The 

 long branch of the distal stem-internode may in different colonies be directed 

 now to the right side now to the left. 



The bifurcate branch-internodes (fig. 6 g), which form the proximal half of 

 the two main branches, have each a 6 and a ;' in common ; but while the branch 

 of the internodes, which is connected with the next branch-internode, has an 

 a and a /9, which latter issues from the proximal part of ;', the branch connected 

 with the zocecium has only a single segment, springing from the end of ;'. The 

 whole internode has only one rosette-plate, situated between /J and y. The bi- 

 furcate internodes, which bear the secondary branches consisting of cylindrical 

 internodes of which generallj' only one, more seldom two occur on each side, are 

 much more slender than the others and thus approach to the form of the suc- 

 ceeding internodes. In these also a single-pored rosette-plate is found between /S and ;'. 



The cylindrical internodes, which as mentioned not only form the terminal 

 part of the two main branches and of the zocecia-bearing secondary branches, 

 but also form one or two secondary branches on each side, are very slender 

 and thin, and their inner cavity has a contracted part at both ends. No rosette- 

 plates are found between the single joints, and they might therefore hardly be 

 regarded as individuals (Bryozoids). 



The number of stem-internodes in the colonies examined is between two and 

 fifteen, and the number of secondary branches ending in cylindrical internodes 

 between nine and fifteen. The number of zooecia in the secondary branches in- 

 creases from without towards the centre and varies in the outermost between 



