56 CALCAREOUS ALGAE OF THE MIDDLE EAST 



Several species, other than the type-species, have been described for Mizzia : e.g. 

 M. yabei Karpinsky, M. japonica Karpinsky, M. minuta Johnson and Dorr, M. 

 bramkampi Rezak, M. cornuta Kochansky and Herak. These are based primarily on 

 differences in segment shape and size, and sometimes on branch-structure. Morpho- 

 logically such species are recognizable taxonomic entities. However, usually they 

 seem to be associated with M. velebitana, and, so far as one can tell from the litera- 

 ture, to be also a minority of the local Mmza-populations. Bearing in mind the 

 variation of segments within a plant, and the environmental local variations in plant- 

 populations, as evidenced by the study of Hillis (1959) on Recent Halimeda, the 

 genus with which Pia compared Mizzia for distribution, it is felt that mostly they 

 may well be, in the botanical sense, of varietal status at best. M. bramkampi Rezak, 

 with its distinctive funnel-shaped branch-structure, appears the one most likely to be 

 a distinct local species. This was described from Saudi Arabia (Khuff formation ; 

 probably Upper Permian) : other species recorded from the Middle East are Mizzia 

 yabei and M. minuta from Turkey (Bilgiitay 1959) ; also M. tauridiana (Guvenc 



1965). 



All the Iraqi Kurdistan specimens seen are referred here to M. velebitana. Occa- 

 sional specimens resembling M. yabei are considered atypical segments of the type- 

 species. One or two specimens resemble some of Endo's figured Eogoniolina, but 

 not his reconstruction, and there is no associated evidence to show that these are 

 other than M. velebitana. Also in the Iraqi material are various specimens corres- 

 ponding to M. cornuta Kochansky & Herak (i960), a species in which the external 

 bulging terminations of the branches (or pores) are roofed over by a thin projecting 

 convex calcareous covering. Setting aside worn material, and many fossil Mizzia 

 segments are recognizably abraded, it would seem that in apparently well-preserved 

 material the pores can be open or closed. This point was discussed in some detail by 

 Pia (1920), who suggested that this difference in the otherwise homogeneous 

 assemblage of segments might possibly be due to the covered pores having contained 

 sporangia. He also drew attention to the effect of light-intensity, varied by shading 

 due to stones, etc. on the calcification of living algae, and to the differences in the 

 calcification of the older and younger segments of the same plant. I believe that in 

 the case of Mizzia light intensity may have influenced this calcification ; in view of 

 what is known of this phenomenon in modern algae, and the random distribution of 

 specimens with roofed pores in Mizzia, the character does not seem worthy of 

 occasioning a distinct specific name. It is true that Kochansky & Herak {op. cit., 

 text-fig. 7) give a longer range for M. cornuta than for M. velebitana in the Jugoslav 

 Permian, but in Iraq at any rate M. cornuta is represented by a small minority of 

 specimens within the main range of M. velebitana. 



Genus MUNIERIA Deecke 1883 



Diagnosis. Dasyclad with thin central stem-cell giving rise to regularly and 

 widely spaced verticils of thin straight horizontal radial side-branches, the whole 

 thickly calcified to give a rigid structure of centrally fused calcified successive 

 whorls. 



