406 



Plate XVIII. 



Fig. 1 



a. Escharina pes anseris (Smitt). The distal 

 end of a zooecium with ooecium. X 75. 



— lb. The distal end of an ordinary zooecium. 



X 75. 



— 1 c. An operculum of the same species. X 75. 



— 2 a. Escharina Dutertrei (Aud.). The vestibular 



arch is seen and also the distal margin of 

 the hinge teeth, which for the most part 

 part are internal. X 75. 



— 2 b. The same species. The distal end of a zooe- 



cium, from the basal aspect, after the basal 

 surface has been partly removed. The high 

 hinge teeth are seen and also the vestibular 

 arch and the processes springing from the 

 latter. X 55. 



— 2 c. An operculum of the sarne species. X 100. 



— 3 a. Schizoporella (Stylopoma) longirostris Hincks. 



X 23. 



— 3 b. The same species. A portion of a colonj' 



with superficial budding. X 23. 



— 3 c. A zooecial aperture of the same species. 



X 75. 



— 3 d. A zooecium of the same species from the 



basal surface. X 40. 



An operculum of the same species. X 100. 

 An avicularium of the same species. X 75? 

 An avicularian mandible of the same spe- 

 cies. X 75. 



Schizoporella {St.) spongiies (Pallas). An ooe- 

 cium is seen, the frontal half of which is 

 cut away. X 40. 



The same species. An ooecium from the 

 proximal end aud distal walls with rosette- 

 plates. X 40. 



— 4 c. Operculum of the same species. X 100. 



— 4d. The same species. Operculum of a colony 



from Java. X 100. 



— 5 a. Petralia japonica (Busk). The lowermost 



zooecium to the left shows a hollow, from 

 which the whole ooecium has been removed; 

 the uppermost to the right shows on the 

 other hand an ooecium with the frontal wall 

 removed. X 40. 



— 5 b. An operculum of the same species. X 75. 



— 3e. 



— 3 f. 



— 3g. 



— 4.1. 



— 4 b, 



10 a. 



11 a. 



Fig. 6 a. Porella (?) cornuta n. sp. The ooecia are 

 furnished with acropetal hollow spine-like 

 processes. X 40. 



— 6 b. An operculum of the same species. X 75. 



(A more correct figure is seen on Plate 

 XXII, fig. 11 a). 



— 7 a. Arthropoma Cecili (Aud.). A developing 



ooecium. X 40. 



— 8 a. Porella margaritifera (Quoy & Gaim.), In 



the bottom of the avicularia the primary 

 ribs of the frontal wall are seen. Both the 

 ooecia and the avicularian chambers show 

 concentric deposits of chalk. X 55, 



— 9 a. A sagittal section through a gonozooecium 



of Hippothoa hgalina L. The ooecium is 

 surrounded by a kenozooecium. 

 A sagittal section through a gonozooecium 

 of Chorizopora Brongniarti Aud. The ooe- 

 cium is surrounded by an avicularium. 

 X 55. 



Haplopoma impressum (Aud.) from the 

 basal surface. The zooecia and the keno- 

 zooEcia surrounding the ooecia are furnished 

 with pore-chambers. X 40. 

 12 a. Smittina akaroensis n. sp. The margin of 

 the ooecia is furnished with an ooecial 

 cover. X 55. 



12 b. An operculum of the same species. X 100. 



13 a. Emballotheca qvadrata (Mac Gilliv.). Six 

 different zooecia take part in the formation 

 of the ooecium figured. X 23. 



13 b. The aperture of a zooecium of the same 

 species. X 75. 



An operculum of a gonozooecium of the 

 same species. X 55. 



An operculum of an ordinary zooecium of 

 the same species. X 55. 



13 e. An avicularian mandible of the same spe- 

 cies. X 75. 



14 a. Eurysiomella foraminigera (Hincks). Two 

 gonozooecia and an ordinary zooecium. X 40. 



14 b. The same three zooecia, from the basal 

 surface, which has a large uncalcified cen- 

 tral part. X 40. 



14 c. A sagittal section through a zooecium with 

 ooecium. The ooecium and the covering 

 kenozooecium are seen. X 40. 



— 13 c. 



13d. 



