On the structure and affinities of the genus Monticulipora and its sub-genera, with critical descriptions of illustrative species . stinct from this, and distinct from oneanother. Considering, therefore, that almost all the determina-tions of M. petropolitana, in different deposits and in differentcountries, have been based solely upon macroscopic investiga-tion, and that this is clearly insufficient for specific diagnosis,it has appeared to me to be quite useless to give any synonymyof the species. With our present knowledge, in fact, such asynonymy would simply give us the information that c
On the structure and affinities of the genus Monticulipora and its sub-genera, with critical descriptions of illustrative species . stinct from this, and distinct from oneanother. Considering, therefore, that almost all the determina-tions of M. petropolitana, in different deposits and in differentcountries, have been based solely upon macroscopic investiga-tion, and that this is clearly insufficient for specific diagnosis,it has appeared to me to be quite useless to give any synonymyof the species. With our present knowledge, in fact, such asynonymy would simply give us the information that certainauthors had identified from certain regions and formationscorals which are doubtless referable to Monticulipora in itswide sense, and which resemble ]\L petropolitana in form andhabit. In the Swedish specimens of M. petropolitana, Pand., whichI shall take as the type of the species, the corallum has thewell-known hemispherical or sub-globular form, its circular and S UB- GENUS DIPL 0 TR YPA. 159 concave base being covered with a thin concentrically striatedepitheca (fig. 30, a and b). In thin sections no feature is more. 30.—JMottticjilipora petropolitana, Pander. A, A specimen viewed in piofile, of tlienatural size ; B, Under view of the same, showing the basal epitheca, of the naturalsize ; c, Part of a tangential section of tlie same, enlarged twenty times ; D, Partof a vertical section of the same, enlarged twenty times. From tlie Lower Silurian rocksof Sweden. striking than the extreme delicacy and tenuity of the walls ofall the corallites. The walls are so thin that they appear asmere simple and undivided dark lines, the originally duplexcharacter of the boundaries between contiguous corallitesbeing entirely lost. Nor, again, do the walls become in anyway thickened as the surface is approached. In this respect,therefore, there is a marked and important difference in thestructure of this form as compared with the more normal typesof Monticulipora {Heterotrypa). In
Size: 1982px × 1261px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthornicholso, bookcentury1800, bookdecade1880, bookyear1881
