FAUNAL SUCCESSION IN THE LOWER CARBONIFEROUS LIMESTONE. 191 
ADDENDUM. 
Exametes oF Use or ZoNAL SCALE. 
Evolutionary Phenomena illustrated by the Coral Sequence. 
PHYLOGENETIC OLD AGE is indicated by a vesicular and indistinctly septate 
peripheral zone—as in Caninia gigantea and in Lonsdalia. 
Compounp forms succeed simple ones and, probably, to all compound species 
there is a simple ancestor: Cyathophyllum regium is the culmination of the 
Cyathophylla; simple Lonsdalia precedes (in D,), and accompanies (in D,), the 
entrance of ‘ Lonsdalia floriformis’; Lonsdalia duplicata is a compound and 
specialised Dibunophyllum. 
PARALLEL DEVELOPMENT is illustrated in the closely allied genera Lithostrotion 
and Diphyphyllum; the very narrow Diphyphyllum, D. gracile of D,, succeeds the 
broad D. lateseptatum of D,, just as the very narrow Lithostrotion, L. junceum of 
D, succeeds the broad Z. martini of 8. 
CoBVAL ASSIMILATION is exhibited by the Cyathophylla which are Zaphrentoid 
(C. patula), Caninoid (Cyath. @), or Clisiophylloid (Cyath. murchisont), according 
to the dominant ‘ tone’ of the age. 
DIRECT AND CONTINUOUS VARIATION is exhibited in the Koninckophylla from 
D, to D,, in the Cyathophylla from y to D, and in the Debunophylla. 
PERSISTENCE OF SPECIES is illustrated by the great Clisiophyllid trunk-line. 
Already highly developed in C. omaluzst of the Uppermost Devonian, this gens of 
Clisiophyllum reappears in y, becomes common in C, and attains a maximum (in a 
well-marked variant, C. ingletonense) at S,; it still persists into Dy, where the 
difference from the Devonian ancestor is remarkably small. Caninia cornucopie is 
another example; the gens starts at the top of Z, reaches a maximum in early 
C, and reappears, in D, and D,, in a mutation which differs but slightly from the 
early form. 
ACCELERATION OF VARIATION on approaching extinction is beautifully illus- 
trated by the large number of closely linked sub-genera into which the main 
Clisiophyllid section divides in D,, e.y., Aspidophyllum, Rhodophyllum, Histio- 
phyllum, Cymatiophyllum, §c. 
Occupation of a Table at the Zoological Station at Naples.-—Re- 
port of the Committee, consisting of Professor 8S. J. Hickson 
(Chairman), Rev. T. R. R. STespsine (Secretary), Sir E. Ray 
LANKESTER, Professor A. SEpDGwIcK, Professor W. C. 
McIntosu, Dr. S. F. Harmer, and Mr. G. P. Brpper. 
_ Tue table at the Zoological Station at Naples has been fully occupied 
_ during the past session. Thanks to the kindness of Dr. Dohrn two or 
_ more nominees of the British Association Committee have, on occasions, 
~ been allowed to work in the station at the same time. 
_ The following naturalists have occupied the table since the date of 
our last report :— 
Mr. W. J. Dakin, B.Sc., University of Liverpool. 
Mr. H. O. S. Gibson, B.A., University of Oxford. 
Colonel Shepherd, Indian Army. 
Mr. F. F. Dreyer, B.A., University of Cape Colony. 
Mr. Charles Martin, B.A., University of Oxford. 
