CALCAREOUS ALGAE OF THE MIDDLE EAST 81 



Trinocladus tripolitanus Raineri 

 (PI. 24, figs. 3, 4) 



1922 Trinocladus tripolitanus Raineri : 79, pi. 3, f. 15, 16. 



1936 Trinocladus tripolitanus Raineri ; Pia : 5, pi. 2, text-fig. 3. 



i960 Trinocladus tripolitanus Raineri ; Elliott : 224. 



1966 Trinocladus tripolitanus Raineri ; Massieux : 114, pi. 2, fig. 1. 



Description (based on Pia). Tubular cylindrical dasyclad, probably slightly 

 club-shaped, length (observed) up to 3-36 mm., external diameters (different parts of 

 thallus) from 0-47-0-68 mm., corresponding internal diameters 0-16-0-19 mm. (34- 

 28%). Successive verticils, 9 or 10 per mm. of tube-length, are each of about 8 

 horizontally-directed branches, which usually are not alternate in position in 

 successive whorls. Each primary branch is club- or paddle-shaped in transverse 

 section, widening rapidly from a narrow junction with the stem-cell and extending 

 outwards through about half the wall-thickness : it then gives rise in turn to several 

 smaller but similarly-shaped secondaries (perhaps five or six), and each of these in 

 turn to a cluster of about six slim short tertiaries reaching the exterior as pores. 

 Branches from lower verticils do not show tertiaries and may have been sterile. 



Horizon. Cenomanian or Turonian of Libya, North Africa (Raineri 1922 ; 

 Pia 1936) : Turonian of France (Pfender 1940) and of Iraq and Trucial Coast, 

 Arabia : Upper Cretaceous of Czechoslovakia (Andrusov 1939). 



Material. Subsurface Turonian of Ras Sadr no. 1 well, Abu Dhabi, Trucial 

 Oman, Arabia, and of Musaiyib no. 1 well, Hilla Liwa, Iraq. 



Remarks. The Middle East occurrences of this species are known only by 

 random thin-sections, which however correspond well in dimensions and detail to 

 those of the Libyan type-material ; external diameters observed are 0-650-0-702 

 mm., with corresponding internal diameters of 0-182-0-208 mm. (28-30%). More- 

 over, other algae associated at the type-locality are also seen in the Middle East 

 occurrences : Dissocladella undulata (Raineri) Pia at both localities and the codiacid 

 Boueina pygmaea Pia as well at Ras Sadr. 



Trinocladus perplexus Elliott 

 (PI. 24, figs. 1, 2, 6, 7) 



1955b Trinocladus perplexus Elliott : 128, pi. 1, figs. 16-18. 

 i960 Trinocladus perplexus Elliott ; Elliott : 225. 



Description. Tubular cylindrical calcified dasyclad, probably originally slender 

 club-shaped. Length (incomplete) up to 2-5 mm. seen, with external diameters 

 increasing from about 0-32 to 0-44 mm., and the proportion of internal diameter to 

 external constant at 53%. Fragments of smaller examples of 0-26 mm. diameter 

 show an internal diameter of only 40%. The wall shows consecutive horizontal 

 verticils of lateral branches : in the large example quoted the verticils are spaced at 

 about 17-19 per mm. in the lower, slimmer portion of the tube, diminishing to about 

 12 per mm. later. Each verticil consists of 7-10 branches : these communicate 

 with the stem-cell cavity by rounded-rectangular pores. Each short thick primary 



