26 CALCAREOUS ALGAE OF THE MIDDLE EAST 



and tube-walls, divided by horizontal floors into successive compartments, each of 

 these itself divided by radial septa into several chambers each communicating by a 

 single pore with the axial tube, and by numerous pores with the exterior, riddling the 

 outer wall. Pores opening in the axial tube set in regular verticils ; external pores 

 set in irregular sinuous lines. 



Broeckella is a peculiar dasyclad described by Morellet (1922) from the Belgian 

 Montian, and subsequently recognized from about the same level in Austria and Cuba 

 (Keijzer 1945). These occurrences are of the type-species, B. belgica Morellet : 

 B. ranikotensis (Walton) is known from the Indian Palaeocene (Walton 1925 ; Pia 

 1928), and the little B. minuta Carozzi from Switzerland is presumed Palaeocene. 



Broeckella as described by Morellet (1922) is an extinct dasyclad whose skeletal 

 remains occur as little keg- or short barrel-shaped units. Each unit contains a fairly 

 wide central canal extending vertically from end to end, which once housed the main 

 stem-cell of the plant. The apparently thick structure between outer surface and 

 inner central canal is hollow, being divided by thin horizontal platforms into annular 

 cavities, which are themselves divided into segment-shaped chambers by thin radial 

 vertical walls. Each of these chambers (primary branches) communicates with the 

 exterior by numerous small pores in the outer wall, said to open in sinuous lines, and 

 with the interior canal by one large pore each, through the inner wall, arranged in 

 horizontal rings. The distinctive thin-section appearance has been very well figured 

 by Keijzer (1945). The numerous relatively large interior cavities between inner 

 and outer walls have irregular surfaces to septa and partitions, made still more so by 

 secondary calcification, and random cuts give curious irregular-radial patterns not 

 like those of more conventional dasyclads such as Cymopolia, where there is a greater 

 proportion of wall-material to original cavity in life. 



The wide but scattered Tethyan distribution of this genus, its probable ancestry 

 and its restricted geological range have been discussed (Elliott 1962b) ; I concluded 

 that it was a primitive genus occurring uncommonly even under optimum algal 

 conditions in the Palaeocene, and then becoming extinct. 



Broeckella belgica L. & J. Morellet 

 (PL 3. fig. 1) 



1922 Broeckella belgica Morellet : 22, pi. 2, figs. 56, 57. 



1945 Broeckella belgica Morellet ; Keijzer : 178, pi. 6, figs. 84-86. 



i960 Broeckella belgica Morellet ; Elliott : 225. 



1962 Broeckella belgica Morellet ; Elliott : 51. 



Descriptions. The characters of this, the type-species, are those of the genus. 

 The Middle Eastern material consists of random thin-sections only, similar to 

 Keijzer's Cuban material. Of described species, the Indian B. ranikotensis (Walton) 

 is the largest, and the Swiss B. minuta the smallest : the Belgian Cuban and Middle 

 East specimens are all referred to B. belgica Morellet. Some dimensions for com- 

 parison are listed below. 



