CALCAREOUS ALGAE OF THE MIDDLE EAST 33 



verticil diameter. Tubules circular in cross-section, terminally bluntly rounded, 

 thin-walled (wall-thickness 0-026 mm. in a tubule of outer diameter 0-130 mm. ; 

 verticil-diameter 1-5 mm. approx.), and forming a moderately developed raised 

 central ring below, but without similar feature above : the tubules communicate 

 with the central cavity each by a single pore. 

 Horizon. Valanginian of Algeria and Oman. 



Material. Found in the basal Cretaceous (Lower Thamama equivalent) of 

 Hugf, Southern Oman, Arabia, i.e. at about the same horizon as the type-level in the 

 Algerian Valanginian, and similarly associated with Clypeina lucasi Emberger, and 

 also with the codiacid Arabicodiurn aegagrapiloides Elliott. 



Remarks. Clypeina niarteli is highly distinctive amongst species of its genus : 

 the only other stellate species in which the radiating tubules are similarly free for 

 much of their length are Clypeina digitata (Parker & Jones) Morellet emend. Rezak, 

 and (less closely comparable) C. helvetica Morellet, both Eocene. Emberger's com- 

 parison with the former drew attention to the gently concave plane of C. marteli as 

 compared to the more funnel-shaped form of C. digitata, a valid distinction (Emberger 

 1956). C. marteli, however, does show a central fusion ring, marginal to the stell-cell 

 cavity, on its lower surface, though this is regular in form and not irregular as that of 

 C. digitata described by the Morellets (1913). 



More serious risk of confusion exists with Actinoporella podolica Alth, which 

 similarly occurs at about Valanginian level in the Middle East. However, although 

 both are somewhat similar in size, Actinoporella shows many more tubules per 

 verticil (18-20 as opposed to 7-12, and the former smaller in size), and a propor- 

 tionally larger central cavity (d/D 20% or more, as opposed to 10-14% m C. marteli). 



Clypeina parvula Carozzi 



(PL 5, figs. 5, 6) 



1946 Clypeina parvula Carozzi : 24, fig. 1. 



1948 Clypeina parvula Carozzi ; Carozzi : 355, figs. 50, 51. 



1955b Clypeina parvula Carozzi ; Elliott : 126. 



i960 Clypeina parvula Carozzi ; Elliott : 222, 223. 



Description (after Carozzi). Sterile whorls in the form of straight thick-walled 

 calcareous tubes, widening in the upper portion and with the outer surface showing a 

 number of shallow straight vertical flutings or concavities, usually about twelve, but 

 from ten to twenty-five recorded. The fertile whorls are similar but widen much 

 more, terminating in a kind of peripheral fringe or collar : internally, sporangial 

 chambers correspond to the external flutings, the actual cavities being set in the thick 

 calcareous wall. External diameter is said to be from 0-09-0-45 mm. and the 

 diameter of the central canal 0-03-0-12 mm. (average 0-07 mm.). 



Horizon. Upper Jurassic — bottom Cretaceous Europe (PAptian-Albian Jugo- 

 slavia, see Radoicic i960), bottom Cretaceous Middle East. 



Material. In Iraq, from the lower part of the Cretaceous (about Valanginian 



