68 A. E. Yerrill — Bernmdian and West Indian Reef Corals. 



and ridges. Many large specimens of t3'pical Diploria have both 

 single and double ridges on their different parts, or even side by side, 

 and the same is true of Manicina. The calicles may form long 

 series, more or less winding, or they may be short, or even circum- 

 scribed, equally in Diploria^ Coeloria, and Mmandrina E. and H., 

 and these variations are often seen on a single specimen of either 

 group. They all form radial infoldings or collines at the margins, 

 when young. Resorption of parts of the collines is frequent. 



In Diploria and Manicina E. and H, and probabl}^ in the other 

 groups, the ends or other parts of the growing ridges often expand 

 and give rise to new zooids, and thus form new actinal grooves by 

 extracalicinal budding. Therefore the intervening ridges in such 

 cases are necessarily simple for a time. See pi. x, figs. 1-8. 



The genus Mmandra, as restricted above, would include the fol- 

 lowing four common West Indian species, two of which are found 

 at the Bermudas,* 



Besides these there are two or three other rare West Indian 

 species that are not well known. One of these [M. varia), which was 

 described by Dana as Astrcea varia, is remarkable for having a large 

 part of its surface covered with cii'cumscribed polygonal calicles like 

 those of Goniastroea, to which genus it has usually been referred. 



But simple or multiple circumscribed calicles also occur, more or 

 less frequently, in all the other species, and they are often due to 

 extracalicinal budding and subsequent division. There is a large 

 specimen of 31. clioosa in the Museum of Yale University which 

 has a large part of its surface covered with simple angular calicles, 

 while in other parts they are long and meandriniform, as usual. The 

 same is true of some of the East Indian species of the Cmloria-grouip. 



In the Indo-Pacific region, including the Red Sea,f there are a 

 considerable number of nominal species of Mmandra, most of which 

 have been referred to CoeloTia and Leptoria. 



* Nelson (Trans. Geol. Soc. London, v, p. 112) records the occurrence of M. 

 areolata as a fossil in the older beach rock. Probably his specimens are the 

 same that Mr. Vaughan has recently identified as Mycetophyllia Lamarckana 

 (in coll. Geol. Soc). Neither of these species has been found living at the 

 Bermudas, but the older "beach rock " there contains also several West Indian 

 shells that no longer exist in the Bermudas, indicating a period of warmer 

 climate than at present. This rock may be post-glacial in age. It is overlaid 

 by several forest or red-clay beds with much eeolian limestone interstratified. 



f See Klunzinger, C. B., Die Korallthiere des Rothen Meeres. Madreporaria. 

 Berlin, 1879. In this excellent work there are good descriptions and photo- 

 graphic figures of five species and four varieties of Cceloria and of one species 

 of Leptoria. 



