46 CALCAREOUS ALGAE OF THE MIDDLE EAST 



Genus DISSOCLADELLA Pia 1936 



Diagnosis. Small tubular dasyclads, usually thin-wallecl with wide stem-cell 

 cavity and often annular, each verticil showing horizontal branches with a short 

 distally-swollen primary dividing into a bunch of short secondaries, usually four in 

 number and terminally widening. 



Dissocladella deserta sp. now 



(PI. 10, figs. 7, 8) 



i960 Dissocladella sp. Elliott : 225. 



Description. Small hollow calcareous cylinder, straight-sided with rounded 

 ends, length about 075 mm., external diameter 0-39-0-47 mm., internal diameter 

 0-23-0-29 mm., verticils of about twelve branches each set 0-13 mm. apart vertically; 

 branches showing a short primary, swollen to varying degree, and then dividing into 

 four straight divergent secondaries which widen terminally to external pores. 



Horizon. Palaeocene and Eocene of the Middle East. 



Syntypes. The specimens figured in pi. 10, figs. 7, 8, from the Umm er Radhuma 

 (Palaeocene-Lower Eocene) Formation of Wagsa and Aidah, Diwaniyah Liwa, S.W. 

 Iraq. V. 52066, 67. 



Other Material. Very numerous random thin-sections from the same horizon 

 and general area, and subsurface in the Basra oilfields, S. Iraq. Also from the 

 Palaeocene Seiyan limestone of Wady Ghabar, Hadhramaut, S. Arabia. It may 

 occur in the Lower Eocene of Egypt (see below). 



Remarks. This little Dissocladella, although very common, occurs in a porous 

 microcrystalline dolomitic limestone and is always very poorly preserved, the 

 structures showing as cavity-patterns amongst the pores and crystals. Although 

 recognized some years ago, better material has not been found, and it is now 

 described. It may well be the same as the " Dactylopora " sp. of Schwager (1883) 

 from the Lower Eocene " Libyschen-Stufe " of Egypt, as remarked by Pia (1936b) ; 

 the latter's comment on the relative sizes is an error. 



Dissocladella undulata (Raineri) Pia 

 (PI. 11, figs. 4-6) 



1936a Dissocladella undulata (Raineri) var. ; Pia : 4, pi. 1. 



i960 Dissocladella undulata (Raineri) ; Elliott : 224. 



1966b Dissocladella undulata Raineri ; Massieux : 115, pi. 2, figs. 2, 3. 



Description (detail after Pia). Small hollow calcareous cylinder, length about 

 1-4 mm., external diameter 0-24-0-32 mm., internal diameter 0-08-0-10 mm., with 

 close-set verticils showing about 8 primary branches. These are narrow at the 

 junction with the stem-cell and widen outwards, finally dividing into about six 

 secondaries of similar shape which widen to the outer surface. 



