CALCAREOUS ALGAE OF THE MIDDLE EAST 13 



similar structures in related groups, reflects attempts towards a real understanding 

 of evolution, and dissatisfaction with rigid morphological classification, however 

 logically contrived. The subjective elements in such reasoning, normally sub- 

 ordinate, become much more apparent when subdivision is attempted of a relatively 

 homogeneous biological group. In the " small change " of evolution personal 

 choice in detailed classification becomes obvious. Thus Clypeina has been referred 

 both to the Diploporeae (Pia 1927, Emberger 1944) and to the Acetabulareae 

 (Morellet 1913 ; 1922 ; 1939 ; Rezak 1957). Since clypeiniform remains are now 

 recorded Irom the Permian (p. 36) it seems possible that the different morphological 

 trends seen in dasyclads may have evolved more than once, and the classification of 

 such similar forms is difficult. In the present work Clypeina is placed in the new 

 tribe Clypeineae : the reasons for this and the relationship of the genus to Adino- 

 porella, here left in the Diploporea, are discussed below (p. 99). 



In the Dasycladaceae considered here, the increasing complexity of branch- 

 structure, and transference of position of reproductive structures already mentioned, 

 are noticeable evolutionary trends. It is inevitable, however, that in classifying 

 fossil genera represented by very varied results of superimposition of localized 

 calcification on different stages of these trends, that frequently some uncertainty 

 should be felt as to the appropriate tribe. The Middle Eastern genera and species 

 described below have been so referred in accordance with literature quoted. For 

 many genera, simple or complex, e.g. Diplopora or Neomeris, there is no uncertainty. 

 For others, e.g. Atractyliopsis or Griphoporella, the nature of the fossil ensures its 

 relegation as incerta sedis. Between these extremes are several doubtful cases, 

 assigned here to a tribe for consistency, in accordance with published accounts ; 

 e.g. Cylindroporella to Diploporeae (Kamptner 1959) and Terquemella to Dactylo- 

 poreae (Morellet 1922 ; Emberger 1944). Pagodaporella is assigned to Dasycladeae, 

 in view of its analogy with Dasycladus. Mizzia is placed under Diploporeae follow- 

 ing Rezak (1959b), and Acroporella also, in view of its author's opinion on its relation 

 to Salpingoporella (Praturlon 1964). The writer is in agreement with the need for 

 subdivision of the Diploporeae expressed by Rezak (1959a : 125), but has not 

 attempted this, still less general reclassification of dasyclad tribes, in the present 

 study of Middle East representatives of the family. The recent discovery of a 

 Dissocladella in the older Mesozoic (Ott 1965), and the phylogenetic considerations 

 given by this writer, show how random and incomplete is the evidence for major 

 re-classification. 



The table given, therefore, represents current conventional taxonomic assignment 

 of the genera listed, which are dealt with alphabetically in the main descriptive part 

 of the work, where the synonymies are selected to cover primary descriptions, 

 revisions and Middle East occurrences only. 



Family DASYCLADACEAE Kutzing 1843 

 orth. mut. Hauck 1884 



Tribe DASYPORELLEAE Pia 1920 

 A nthracoporella 



