124 REPORT ON THE SPECIMENS OF THE GENUS MILLEPORA 



colony, but it is the best for showing the intermediate stage between the branching 

 form and the lamellar form which the colonies so frequently assume when growth 

 has proceeded further. I have very carefully compared this specimen with- the one 

 s*hown in Figure 4 and with several specimens of the facies dickotoma, young and 

 old. Neither the texture, size of the pores, average number of dactvlopores to each 

 gastropore nor any other feature indicates that we have here more than one species. 

 A fragment of the specimen in Figure 2 cannot be distinguished by any characters 

 from a fragment of the same size taken from the specimen shown in Fig. 4 nor 

 from a specimen of the facies dichotoma unless it be a slight difference in colour or 

 the number and size of tubercular processes on the surface. 



Fig. 5 is a photograph of a specimen which under the old system would have 

 been included in the species M. nodosa Esp. which closely resembles in form, as 

 pointed out by Moseley (I.), Milne Edwards's M. gonagra \el 21. tuberculosa. 



Moseley thought that a good character of this species is that the pores are 

 distributed over the surface in well-marked systems. I cannot agree with this 

 conclusion because in the two specimens in this collection the degree of definition 

 of the systems varies enormously. An examination of Fig. 5 with a magnifying glass 

 shows that iu the lower half of the specimen the systems are very well marked, 

 whereas in the upper half and at the edge the pores seem to be distributed 

 indiscriminately. A better example of the variability of this feature in Millepora 

 may be seen in Fig. 3 where the systems are perfectly distinct on the flat surface 

 of the corallum but completely fused on the tubercles and at the edges. 



Specimen of Irregular Facies. 



The large specimen of which a photograph is given in Fig. 7, presents us with 

 so mauy different forms of growth that if pieces of it were judiciously broken off 

 they might under the old system be placed in at least three different species. The 

 upright flattened plate to the left in the figure with a relatively smooth flat surface 

 would be included in the species M. complanata ; the tuberculate knob on the right 

 corresponds fairly well with the descriptions of M. gonagra v. tuberculosa of Milne 

 Edwards ; while the central parts might be considered to belong to the species 

 M. verrucosa. Two important factors have brought about the irregularity of this 

 specimen. 



In the first place the specimen to a certain extent assumed the shape of an 

 irregular lump of coral conglomerate on which it grew. During the transmission of 

 the specimen the crust of live coral on one of the most prominent knobs was broken 

 off and reveals an underlying knob of dead coral. This is shown in the photograph 

 Fig. 6. This protuberance then which would have looked perfectly natural in the 

 unbroken fragment was due not to any intrinsic tendency of growth of the species 

 but to the chance form of the lump on which the individual specimen happened to 

 be growing. 



In the second place the irregular warty or tuberculate surface of the corallum 

 is largely due to the influences of parasitic barnacles. 



