5G me. staxley smith ox [March 1913, 



to the genus Aulophyllum ' (pp. 480-81), his reasons being the 

 presence of what he considered the columella. The following 

 species were described by him : — 



Cyclophyllum : 



C. fwngites, C. ureanum, C. bowerbanJci, 1 C. biacmninaium, C. pachy- 

 endothecum, C. ohovatum, C. scoulerianum, C. duncanianum, C. ellipticum, 

 C. orbieulum, C. carpenterianum, C. hennieanum, C. m'kcndrickianum, 

 C. curvilineare,* C. concentricum, C. cylindricum, C. frondicum* C. tor- 

 tuosum, C. paradoxacum* C. inter •medium, C. radianum* C. moseleyanum, 

 C. vesicularum. 



Aulophyllum : 



A. patricJrianwm* A. fwngites, A. edwardsianum, A. haimeianum, 

 A. wiinschianum, A. impingeum, A. expanmm. 



These different species are carefully figured, and, with the ex- 

 ception of those indicated by an asterisk (which appear to be 

 Clisiophylloid forms), 2 agree very closely in plan. The differences 

 expressed in the figures : that is, the size, shape, and structure of 

 the central axis, the width of the space between the axis and the 

 ends of the septa, and the character of the outer zone of the fine 

 dissepiments, may be assigned to individual variability and to the 

 particular stage of development of the corallum at which the section 

 was cut. Plate-space will not allow full demonstration of these 

 assertions, although the opinions here expressed result from the 

 examination of many sections. Nevertheless, figs, ba-bc & 7a-7b 

 in PI. V, and 1 a-1 c in PI. IX, illustrate the marked difference 

 existing between sections from the same coral. Furthermore, 

 the longitudinal sections 4 6 in PI. VI &, 3 b in PI. VII show by 

 the variable character of the central tissue how sections cut at 

 different horizons must necessarily vary. 



The results of my investigation, therefore, lead me 

 to regard all Thomson's species (with the exceptions 

 before noted) as possible varieties of one species. My 

 conclusions respecting the identity of Aulophyllum and Cyclo- 

 phyllum have been anticipated by opinions expressed by both 

 Dr. A. Vaughan [13] and Mr. R. G. Carruthers [14]. 



III. Sources of Material Studied. 



The following table shows the localities from which the corals 

 examined were obtained, and the palaeontological horizon of the 

 beds in which they occurred. Accounts of the Lower Carboniferous 

 palaeontology will be found in the papers mentioned in the list of 

 authorities below ; reference-numbers to these are given in the 

 third column : — 



1 Cyclophyllum howerhanJci Thomson does not answer the description of 

 Aulophyllum bowerbanki Ed. & H. 



2 In the absence of the original type-specimens, which were unfortunately 

 destroyed by fire, any critical survey of Thomson's types is inadvisable. 



