402 



Plate XVI. 



Fig. 1 a. A .sagittal section through a colony of Has- 

 wellia coronata (Reuss). Three ooecia are 

 seen. X 17. 



— 1 b. An operculum of the same species. X 140. 



— 2 a. A sagittal section through Haswellia aus- 



traliensis (Busk). The four lowermost zooe- 

 cia with ooecia. X 17. 



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



— 3 a. Tubucellaria hirsuta (Lamx.). The four 



lateral zooecia with peristomial ooecia. X 17. 



— 3 b. A sagittal section through the same species. 



The two lowermost zooecia with ooecia. X 23. 



— 3 c. Operculum of the same species. X 75. 



— 3 d. A separating wall with rosette-plates, the 



position of which is at the proximal end of 

 each of the thread-shaped appendages. X 200. 



— 3 e. A part of the surface of a zocecium of the 



same species. The ascopore is seen dlstally. 

 X 75. 



— 4 a. Tubucellaria opuntioides (Pall.). Five ooecia 



are seen. X 12. 



— 4 b. A sagittal section through the same species. 



Two ooecia are cut through. X 23. 



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



— 4 d. The same species. A part of the surface of 



a zooecium. The ascopore is seen distally. 

 X 55. 



— 5 a. Tubiporella magnirostris (Mac Gilliv.). Two 



peristomial ooecia are seen. X 23. 



Fig. 5 b. The same species from the basal aspect 

 after removal of the basal surface. Two 

 ooecia (which are however ^not correctly 

 shaded) are seen, and the three zooecia show 

 a distinct vestibular arch. X 23. 



— 5 c. The same species. A part of the surface of 



a zooecium. X 55. 



— 5 d. A sagittal section through the same species. 



An ooecium is seen proximally, and the two 

 zooecia show a vestibular arch at the be- 

 ginning of the peristomial tube. X 17. 



— 6 a. Lekythopora hystrix Mac Gilliv. Three ooe- 



cia are seen. X 65. 



— 6 b. A sagittal section through an ooecium of 



the same species. X 23. 



— 6 c. An operculum of the same species. X 55. 



— 7 a. A sagittal section through Lekythopora stel- 



lata (Busk). Two ooecia are seen. X 17. 



— 8 a. Euthyroides Jellgae n. sp. X 40. 



— 8 b. The distal end of a young zooecium of the 



same species. The frontal surface is calcified 

 right up to the operculum. X 75. 



— 8 c. The distal end of an older zooecium in which 



a resorption of the chalk has taken place 

 proximally to the operculum. The two hol- 

 low spines are formed, which cover the 

 entrance to the compensation-sac. X 75. 

 > — 8d. An operculum of the same species. X 100. 



— 8 e. An avicularian mandible of the same spe- 



cies. X 40. 



