4y 



perhaps be described as Turbinolids with a fenestrated wall, 

 while the remainder are intermediate in character. So far as 

 development is concerned, there can be but little doubt that 

 T. CJarkii, the Miocene species, has descended from T. fenestratus^ 

 a widely spread Eocene coral. Again, T. Kiisoni is specially 

 characteristic of certain Eocene beds antecedent in age to those 

 from which the closely allied forms T. complanatus and T. latero- 

 plenus have been recorded. The calice of T. Kiisoni is very 

 similar to that of T. lateroplenus — and, indeed, almost the only 

 important difference between the two corals is that in the latter 

 the mural pores completely penetrate the wall, while in the 

 former they do not. On the strength of such striking analogies 

 between these species, I venture to suggest that the younger of 

 the two has been derived from the older. I may add that 

 T. fenestratus ranges throughout the Eocene, while T. decUvis is 

 restricted to a single outcrop, which I correlate with the older 

 beds. 



The above suggestion of mine touches, of course, upon a debate- 

 able question, viz., the development of the perforate type of 

 corals from the ncn-perforate. Instead of attempting to discuss 

 this subject myself, I prefer to direct attention to the able 

 remarks made upon it by Dr. J. W. Gregory in the Introductory 

 Note to his Monograph of the Jurassic Corals of Cutch."^ It 

 will be seen by the following short extract from that work that 

 the genus I am now dealing with is regarded as an important 

 factor in the question at issue : — 



" It is true that there are some remarkable resemblances 

 between the three families of Perforata and the three groups of 

 non-perforate Madreporaria. The simple Eupsammidse are in 

 many ways like the Turbinolidse. . . The parallelism between 

 the groups of cainozoic Perforata and mesozoic non-perforate 

 corals may be either a case of homoplastic modifications in two 

 series of corals, or it may indicate that the three families of 

 Perforata have descended from different members of the non- 

 Perforata, the porous character of the later corals being indepen- 

 dently acquired, like the bipedal habit of birds, of some reptiles 

 and some mammals. 



"The latter explanation would necessitate the dismemberment 

 of the group Perforata, and it appears to be supported by the 

 asserted occurrence of mural pores in some Turbinolidae. This 

 assertion rests in the main on Trematotrochus, a genus founded by 

 J. E. T.-Woods. . . So far as I am aware, no specimen has 

 been seen in Europe, and the only figure available is the original 

 published by Woods. . . The coral may be one of the 

 Eupsammidse." 



* Pal. Ind., ser. IX., vol. 11. , part II. (1900)^ 



