118 



G. LINDSTRÖM, HELIOLITID^. 



Favosites sp. 

 Fig. 28. Surface, nat. size, to compare with Fav. canadensis. Up. Sil. From Gotland. 



Heliolites porosus Goldfuss p. 



Fie. 29. 



30, 



32. 



33, 



35. 



Typical specinien, with altemating septa, as 

 of two cycles. ^^ i. 

 31. Other specimens with longer septa, f. 31 

 probahly not of final shape, ^V; f- 29—31 

 from Eifel. 



Specimen from Torqua\ , Devonshire, England, 

 with ven" short septa, nearly resembling 

 Hel. interstinctus, from which it however is 

 distinct through the thickened theca. i" i. 

 34. Transverse sections of calicular wall and 

 coenenchvmal tubes to show the microscopic 

 structure with fibrillae. ^^/i. 



Showing the same in longitudinal section, to 

 the right a part of a calicular tube, to 

 the left a coenenchvmal tube. The septal 

 lamella is seen to streteh farther in the 

 calicle and is fainter shaded. The tabulfe 

 are on both sides incrusted bv a growth 



of minute crystals and the clear interspaces 

 are filled with calcareous spar. ^^/i. Spe- 

 cimens fromEifel. 

 Fig. 36. Longitudinal section of a calicular tube with 

 five septal lamellae having serrated edges, 

 probably bases of spines, some fragments 

 of tabulse visible. Specimen from Kerpen — 

 Xollenbach. Eifel. ",i. 

 » 37 I — VII. Two series of opposite changes in the 

 coenenchyma. To the right coenenchvmal 

 gemmation is shown, to the left calicinal 

 degeneratlon or a calicle slowly changing 

 into coenenchyma. Fig. VII represents the 

 fresh surface of the corallum and the other 

 figures were obtained by cautiously abrading 

 the coenenchyma with a knife. '^° i. Both 

 close beside each other on the same spe- 

 cimen. 



