CI.A8SIFICAT0RY POSITION OF SOME MADREPORARIA. 133 



stood, one of the fundamental bases of his classification Dana drew 

 splendid examples, and the whole subject was elaborately discussed 

 by Milne-Edwards and Jules Haime in the first volume of their 

 Hist. jN'at. des Corall. pp. 74-83. 



The illustrations I gave of fissiparity in the " Monograph of the 

 British Fossil Corals," 2nd Ser. Pal. !Soc. 1866, p. 23, and in the 

 earlier plates were copies from the admirable work of Milne-Edwards 

 and Jules Haime. M. de Fromentel was merely the copyist of his 

 predecessors. After reading M. de Eromentel's description of fissi- 

 parity, I fail to find the sentence which states that the waUs are 

 defective, as stated by Mr. Tomes. M. de Fromentel states just 

 the contrary, and explains how the walls of the fissiparous calices 

 may unite with their neighbours and produce polygonal calices. 

 He says, " Bientot les murailles se reserrent entre les deux centres, 

 qui s'ecartent, s'eloignent pen a pen et devieuuent completement 

 independants " (p. 41). It would be indeed remarkable to find 

 distinct corallites, the result of evident fissiparity, without walls ! 



These remarks on the subject of fissiparity are necessary because 

 the particular opinions of Mr. Tomes are utilized in a criticism of 

 MM. Milne-Edwards and his confrere and myself in regard to the 

 fissiparity of Thecosmilia gregaria, M'Coy, sp. Mr. Tomes (p. 168) 

 states tha?t fissiparity and gemmation are sometimes confounded, 

 and proceeds, "Thus the usually accurate observation of MM, Milne- 

 Edwards and Haime failed in the so-called Thecosmilia gregaria to 

 distinguish between them ; and the error of supposing this species 

 increased by division was continued by Prof. Duncan and myself." 



Mr. Tomes withdraws from the company in which he once found 

 himself, and insists that this well-known and most variable species 

 only increases by gemmation. 



I have seen fissiparity, and so did Milne-Edwards and Haime ; 

 and it may be observed m the upper part of Mr. Tomes's own figure 

 (Quart. Journ. Geol. Soc. vol. xxxviii. pi. xviii. fig. 3). 



It is necessary to object to the species Thecosmilia Slatteri^ Tomes 

 (p. 182). The author of it remarks, " This is a small and luell- 

 marlced species^ having much the appearance of Olaclophyllia Baheana, 

 Ed. and H." As the form has a resemblance to a different genus 

 from that in which it is included, the possibility of its being a well- 

 marked one does not exist. At the close of his descrix^tion of the 

 species its author remarks : — " I entertain little doubt that the 

 present species was figured by Prof. Duncan in his ' Supplement to 

 the British Fossil Corals ' as a variety of Cladophyllia Babeana.'' 

 There need be no doubt upon the point; all the details of the 

 figures given by me many years ago coincide with the description of 

 the form by Mr. Tomes. Cladophyllia is really a subgenus of Th&- 

 cosmilia, and Thecosmilia Slatteri^ Tomes, is a variety of Thecosmilia 

 {Gladopjhyllia) Babeana, Ed. and H. 



In concluding my remarks on the criticisms contained in the 

 essay on the Madreporaria of the Great Oolite, it is necessary to 

 allude to the use of the word geniculate again. I found a specimen 



