chief Generic Types of Palaeozoic Corals. 461 



EXPLANATION OF THE PLATES. 



(Unless otherwise stated, all the figures are of the natural size.) 



Plate XXI. 



Fi(j. 1. Clmophyllum Keyscrlingi, M'Coy (?), transverse section of an 

 extremely large example. Lower Carboniferous, Auchenskeoch, 

 Dairy, Ayrshire. 



Fig. 2. Transverse section of a smaller example of the same species ; 

 2 A, longitudinal section of the same, showing the columellarian 

 line and the convex elevated and vesicular tabulae of the central 

 area. Lower Carboniferous, Broadstones, Beith, Ayrshire. 



Fig. 3, CUsiophyUinn bipartitum, M'Coy, transverse section a little 

 below the calice ; 3 a, 3 b, 3 c, transverse sections of the same 

 corallum at different heights, showing the different stages of 

 growth. Lower Carboniferous, Broadstones, Ayrshire. 



Fig. 4. Longitudinal section of C. bipartitum, M'Coy, showing the triareal 

 structm-e ; 4 a, transverse section of the same, showing the great 

 disproportion between the number of the primary septa and the 

 'number of the vertical lamellaj of the central area. Lower Car- 

 boniferous, Bi'oadstones, Ayrshire. 



Fig. 5. ClisiophyUum, sp., transverse section ; 5 a, longitudinal section of 

 the same. Lower Carboniferous. 



Fig. 0. ClisiophyUum, sp., transverse section. Lower Carboniferous, 

 Brockley, Lesmahagow. 



Plate XXII. 



Fig. 1. ClisiopTiylhim, sp., showing the external aspect and the conical 

 boss in the floor of the calice; 1 a, transverse section of the 

 same. Lower Carboniferous, Broadstones, Ayrshire. 



Fig. 2. ClisiophyUum, sp., transverse section. Lower Carboniferous, 

 Langside, Beith, Ayrshire. 



Fig. 3. ClisiophyUum coniseptum, Keys., longitudinal section ; 3 a, trans- 

 verse section of the same. Lower Carboniferous, Langside, 

 Beith, Ayi'shire. 



Plate XXIIL 



Fig. 1. Aspidophyllmn Koninckinnum, Thoms., longitudinal section ; 

 1 a, transverse section of the same. Lower Carboniferous, Third- 

 part, Beith, Ayrshire. 



Fig. 2. Aspidophyllnm e'legans, Thoms., transverse section ; 2 A, calice of 

 the same, showing the helmet-shaped calicine boss. Lower Car- 

 boniferous, Thirdpart, Beith, Ayrshire. 



Fig. 3. A young example of the preceding species, showing the helmet- 

 shaped boss ; 3 a, transverse section of the same. Lower Car- 

 boniferous, Brockley, Lesmahagow, Lanarkshire. 



Fig. 4. Aspidophyllmn, sp., transverse section. Lower Carboniferous, 

 Brockley, Lesmahagow. 



Fig. 5. Aspidophyllum, sp., external aspect, showing the calicine boss in 

 profile ; 5 a, transverse section of the same. Lower Carboni- 

 ferous, Brockley, Lesmahagow. 



