386 



Plate VIII. 



Fig. 1 a. Cellularia rigida, Mac Gilliv. The three zooecia 

 with ooecia. X 40. 



— 1 b. A longitudinal section through two zoCEcia 



with ooecia (ov). At the centre of the broad 

 distal part of each zooecium the narrow 

 proximal part of a neighbouring zooecium is 

 visible. X 40. 



— 1 c. A longitudinal section through a part of an 



internode, which shows developing ooecia (ov). 

 X 40. 



— Id. The same species. A section parallel with 



the frontal surface to show the elongated, 

 narrow shape of the zooecia. X 40. 



— 2 a. Cellularia atlantica (Busk). Four ooecial aper- 



tures are seen. X 17. 



— 2 b. A longitudinal section through a colony of 



the same species. Developing ooecia are seen. 

 X 17. 



— 2 c. The same species, from the basal aspect 



after the removal of the basal surface. The 

 cavities of the zooecia and the ooecia are vi- 

 sible, and here and there external ridges 

 which divide the frontal surface into areas. 

 X 17. 



— 3 a. Micropora Normani n. sp., with calcified 



opercula. X 40. 



— 3 b. A longitudinal section through a zooecium 



of the same species with ooecium. X 40. 



— 4 a. A longitudinal section through a zooecium 



of Micropora perforata (Mac Gilliv.), with 

 ooecium. X 40. 



— 5 a. Foraminella lepida (Hincks). A rudiment of 



an ooecium is seen uppermost. X 40. 



— 6 a. A colony of Chlidonia Cordieri Aud. X 12. 



— 6 b. A colony of the same species with the bran- 



ches in one plane. X 12. 



— 6 c. An internode (kenozooecium) of a main- 



branch with a zooecium rising from it. The 

 segments indicated by n, /S, y and d corre- 

 spond with similar segments in the inter- 

 nodes of the trunk and the main-branches. 

 X 55. 



— 6d. A zooecium, lateral view. The concavity of 



the frontal surface is seen greatly thickened 

 in its distal half; in the distal part of this 

 concavity a smaller one is seen, correspond- 

 ing with the small distal pore in fig. 6 f. 

 Farther backwards is a connection between 

 the frontal concavity and the cavity of the 

 zooecium corresponding to the second pore 

 in fig. 6 f. d. w. — the distal wall. X 55. 



Fig. 6 e. Separating wall with rosette-plate in the 

 stolonate net-work. X 200. 



— 6 f. A zooecium, from the frontal surface. X 55. 



— 6 g. Two internodes (kenozooecia) of a main-branch 



with some of the adjacent zooecia. X 75. 



— 6h. The forked distal internode of the stem. X 75. 



— 6 i. A portion of the stolonate network with the 



proximal part of a stem. X 75. 



— 6j-m. Cylindrical internodes being transformed 



into zooecia by the development of a cup-shaped 

 expansion (the zooecium in an embryo state) 

 from the proximal part of the internode. 

 X 55. 



— 6 n-q. Cylindrical Internodes which apparently 



are changing into zooecia by a gradual swell- 

 ing of the internode. X 55. 



— 6 r. A cylindrical internode with its cup-shaped 



proximal expansion, from the frontal aspect. 

 X 55. 



— 6 s. A transverse section through a zooecium. 



The thick frontal wall, the small concavity 

 (corresponding with the distal pore in fig. 

 6 f.) and the rosette-plate of the distal wall 

 are seen. X 55. 



— 6 t. An internode of the stem, lateral view. Be- 



tween /S and y a distal wall with a unipo- 

 rous rosette-plate is seen. The funnel-shaped 

 concavity is in communication through a 

 pore with the interior of the zooecium. X 75. 



— 6 u. An internode of the stem, from the frontal 



surface. The oval funnel-shaped concavity with 

 its pore is seen. X 74. 

 ~ 6 V. A quite young internode of the stem, the 

 walls of which are still very thin. On ac- 

 count of this the extent of the distal wall 

 (d. w.) is considerable, and the funnel-shaped 

 concavity is not yet developed. In its place 

 is found an oval opening. X 76. 



— 6 X. A young internode of the stem, from the 



basal aspect. The uniporous rosette-plate is 

 seen as also the oval opening. X 75. 



— 6y. A forked cylindrical internode connected 



with two single ones. Between fi and y the 

 distal wall is seen with a uniporous rosette- 

 plate. X 100. 



— 7 a. A longitudinal section through Foveolaria 



elliptica Busk. An avicularian chamber and 

 an ooecium are seen. X 23. 



— 7 b. An articulated operculum of the same spe- 



cies. X 40. 



