54 CALCAREOUS ALGAE OF THE MIDDLE EAST 



Genus MIZZIA Schubert 1907 



1907 Mizzia Schubert : 212. 



1908 Mizzia velebitana Schubert : 382, pi. 16, figs. 8-12. 

 1920 Mizzia Schubert ; Pia : 18. 



1942 Mizzia Schubert ; Johnson and Dorr : 63. 

 1959b Mizzia Schubert (emend) ; Rezak : 534. 



Diagnosis (after Rezak). " The thallus is composed of segments joined end to 

 end in a loosely articulated fashion. The segments are generally disaggregated and 

 are rarely found joined together like a string of beads. Individual segments are 

 spheroidal to cylindroidal or pyriform and are composed of a central cavity 

 (generally barrel-shaped) through which the stipe extended. Radiating from the 

 central cavity are simple expanding, unbranched rays arranged in regular, alternating 

 horizontal rows. At the periphery of the segment the expanded rays are in mutual 

 contact. The alternating nature of the rays and their crowding at the periphery 

 gives rise to a hexagonal (honeycomb) pattern on the surface of each segment. 

 Species are based on shapes and dimensions of the segments and their internal 

 structures ". 



Mizzia velebitana Schubert 1908 



(Pis. 13, 14) 



1908 Mizzia velebitana Schubert : 382, pi. 16, figs. 8-12, text-fig. 5. 



1933 Mizzia velebitana Schubert ; Kiihn : 155. 



1955a Mizzia velebitana Schubert ; Elliott : 83. 



1959b Mizzia velebitana (Schubert) emend. Rezak ; Rezak : 536, pi. 72, figs. 1-3, 5, 6, 8-10, 



12, 13, 15-19. 



1959 Mizzia velebitana Schubert ; Bilgutay : 49, pi. 1, figs. 2-3, pi. 2, fig. 1. 



i960 Mizzia velebitana Schubert ; Elliott : 219. 



Description (from Iraqi material). Hollow, calcareous, bead-like segments, 

 spheroidal, ovoid or elongate-ovoid, pear-shaped or pyriform ; length up to 2-0 mm., 

 external diameter (maximum) up to 2-25 mm., internal diameter measured in the 

 same transverse plane, 60-70% of external ; polar (proximal and distal) openings or 

 gaps in the segment, from 0-18-0-36 mm. diameter in a large segment. Wall 

 perforated by about 12 successive horizontal verticils of coarse pores (short branches), 

 usually 20-25 per verticil over all but the polar ends of the segment. The pores of 

 each verticil are set alternately to those of adjacent verticils, to give the external 

 and surface-tangential section appearance of a large closely-set hexagonal mesh. In 

 vertical section the branches are seen to be wedge-shaped, widening slowly from 

 interior to exterior, and usually of about 0-18 mm. diameter in large examples. 

 Externally the pores may be open or closed : in the latter case they are roofed by a 

 thin externally-convex projecting calcareous covering. 



Horizon. Permian ; North America, North Africa, Europe, Asia. 



Material. In Iraq, common throughout most of the thickness of the Zinnar 

 Formation and the Darari Formation, and occurring rarely in the intermediate 

 Satina Evaporite Formation ; that is, probably from within the upper part of the 

 Lower Permian to near the top of the Upper Permian (but see under Stratigraphic 



