14 Mr. II. M. Bernard on the 



series, like those shown, for instance, in fig. 3. Omphyma is 

 a typical case. 



But this whole process need not detain us ; it has no serious 

 morphological value, being obviously a device for a certain 

 end. When that is attained, it has no further influence on the 

 shape of the skeleton *. 



III. Early flattening out of the Prototheca. — It is obvious 

 that if, by any means, the early prototheca could be trans- 

 formed rapidly into a disk, a broad base could be acquired by 

 the skeleton which would keep it upright. It seems to me 

 clear that the morphology of many of the Palaeozoic corals can 

 be explained on this hypothesis. But the different ways 

 adopted of so changing the primitive conical prototheca seem 

 to have been very numerous, and a review of the forms from 

 this point of view is a desideratum. It is, I believe, along 

 this line that we shall find a more natural set of characters for 

 the revision of such groups as those now included, e. g., in 

 the Cyathophyllidse, than any now adopted. 



In the present place I can only give a few samples, and, 

 to avoid doubt as to the forms meant, I propose to take 

 as examples certain well-known figures accessible to every 

 student. 



" Zaphrentis gigantea" pi. iv. of Milne-Edwards and 

 Haimes's Pol. foss. d. Terr, paleozo'iques. I give this in 

 passing because it is interesting as a very irregular method 

 of acquiring a broad flat base. Diagram fig. 9 ( PI. I.) shows 

 my interpretation of the process. It may be that the coral 

 did not actually become detached and fall over, but that the 

 method may be compared with radicle-formation, only, instead 

 of a narrow lip, the whole side of the prototheca bent out- 

 wards and apparently became cemented to the substratum. 



It will be seen from a comparison with Milne-Edwards and 

 Haimes's figures that in this diagram I am assuming what 

 the early transformation of the prototheca was from the shape 

 of the tabula? in the adult stages; and this is, I believe, 

 perfectly justifiable. Unfortunately not sufficient attention 

 has yet been paid to the variations of the prototheca, which 

 are still to be discovered. In certain types of modifications, 

 e. g. those shown in diagrams figs. 11 and 12, the very earliest 



* Miss Ogilvie's suggested origin of the Perforata from a great elaboration 

 of root-processes so as to form the reticular ccenenchyma is very ingenious. 

 But it is hardly borne out by the development of young jMadrepovidan 

 corals in which the cup- or saucer-shaped prototheca persists as a basal 

 epitheca (see p. 4), and being flattened out from the first has no oppor- 

 tunitv to form radicles. 



