On the structure and affinities of the genus Monticulipora and its sub-genera, with critical descriptions of illustrative species . nsis, NIch., and an abundant but undescrlbed species in theWenlock Limestone of Dudley), which, though primitively,and generally permanently, encrusting, are nevertheless some-times found to attain a considerable thickness, either by thesimple upward growth of the tubes, or by the superpositionof successive layers. Such forms may make a close approachto certain of the Monticuliporoids in general aspect, and maycome to resemble the latter closely in their internal
On the structure and affinities of the genus Monticulipora and its sub-genera, with critical descriptions of illustrative species . nsis, NIch., and an abundant but undescrlbed species in theWenlock Limestone of Dudley), which, though primitively,and generally permanently, encrusting, are nevertheless some-times found to attain a considerable thickness, either by thesimple upward growth of the tubes, or by the superpositionof successive layers. Such forms may make a close approachto certain of the Monticuliporoids in general aspect, and maycome to resemble the latter closely in their internal hope to find a future opportunity of discussing the structureof these peculiar types at greater length. In the meanwhile,therefore, I merely figure their minute Internal structure (), and make a few brief and general remarks. As abovenoted, the general aspect of such forms Is not at all unlikethat of certain Monticuliporcr; but even so far as this Is con- RELATIONS TO EXTINCT ORGANISMS. 87 cerned, there are some peculiarities in the general fades ofthe former which would at once lead the observer to separate. Fig. 14.—Minute structure of Ccrantopora. A, Tangential section of Ccramopora O/iiociisis,Nich., from the Cincinnati Group of Oliio, enlarged eighteen times; B, Part of a longi-tudinal section of the same, similarly enlarged, showing the presence of tabulae ; C, Partof a transverse section of the same, similarly enlarged, showing the thickened cell-walls ;n. Part of a tangential section of an undescribed species of Ceramopora, from the Wen-lock Limestone of Dudley, enlarged eighteen times; E, Vertical section of the same,similarly enlarged, showing the well-developed tabula. them as distinct. Thus, the tubes of which the colony arecomposed always open upon the surface in an oblique manner,reminding one of Alveolites rather than of Monticiilipora, andthe calices are invariably either very irregular in shape, orare, more usually, distinctly crescentic or
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Keywords: ., bookauthornicholso, bookcentury1800, bookdecade1880, bookyear1881
