14 Miss M. M. Ogil vie. Microscopic and Systematic [Nov. 21, 



of the septal spines or inner ends within the tabulate area of certain 

 Palaeozoic genera. The " lamellar " columella is of especial interest ; 

 the author looks upon it as the remnant of a retrograde " main 

 septum" affording therefore an important phylogenetic link between 

 so-called " tetrameral " and " radial " symmetry of the septa wherever 

 it occurs. 



Considerable differences are at present found in Madreporarian 

 literature in the use of the terms "theca"and " epitheca." The 

 author accepts Heider and Ortmann's terms " pseudotheca " for a wall 

 formed by lateral thickening of the septa, and. " eutheca," or simply 

 theca, for a wall in which independent centres of deposit are de- 

 veloped. Ortmann's suborders of Madreporaria, Euthecalia, Pseudo- 

 thecalia, Athecalia are, however, believed by the author to be based on 

 an erroneous principle, since all types with a porous wall are placed 

 among Athecalia. Porosity is looked upon by the author as a secondary 

 feature, the porous wall can be demonstrated to be the morpho- 

 logical equivalent either of pseudo theca or of eutheca. A still more 

 serious objection to these suborders is the fact that not all Turbino- 

 lids possess an eutheca; neither do all Astraeids possess a pseudo- 

 theca as Ortmann means, but cases occur in both those families 

 where the only peripheral support is afforded by the epitheca. The 

 author is inclined to think this was the primitive form of the Madre- 

 porarian calyx, and to look upon both theca and pseudotheca as later 

 modifications associated with retrogression of the epitheca, greater 

 prominence and rapid growth of the septa, and very often with the 

 processes of vegetative budding. 



Certain ccenenchymatous colonies, Madrepora, Turbinaria, &c, 

 have been shown by the author to have thecal and septal structure 

 like the Turbinolids ; further absence of basal structures in the calyx 

 other than columella. This throws a new light on the relationship 

 of these types and brings them along with the Oculinidae and Pocillo- 

 poridae into a very natural affinity with the Turbinolidae. The 

 ccenenchyme of these colonies is treated by the author as an elabora- 

 tion of a primitive extracalycinal deposit around individual polyps. 

 Bourne in one of his papers suggests the possibility of ccenenchyme 

 being epithecate in certain of these types. 



In order to elucidate the " costate " portions of Astraeid and 

 Fungid colonies, the author demonstrates the exact homology of 

 skeletal parts in the calyces of ancient Cyathophyllids and of recent 

 Astraeids and Fungids. The pseudotheca which appeared in Acervu- 

 laria and other Cyathophyllid types marked out an inner from an 

 outer area of the calyx and septa. The exact counterpart of this is 

 found in the type-gemis of the Astraeidae, Heliastraea. In it, how- 

 .ever, only the inner part is called calyx, while the outer area is spoken 

 of as a " coscate" — extracalicinal — area. It is on this outer area 



