218 On Foraminifera found in and about Tubipora musica. 



tion sliow3 either that the section had not passed through the 

 " median ph\nc," or that the helix is trochoid, which is really 

 what the section does represent, judging from those that I have 

 made myself of this Foraminifer. 



EXPLANATION OF TLATE XIII. (figs. 9-29). 



Fig. 9. Carpentcria moniicularis, n. pp., on a portion of Tnhipora musica. 



a, simple form ; h, branclied or dendritic form ; c c, apertures re- 

 spectively ; d, lines or grooves marking the septal limits of the 

 Chambers. Magnified four diameters. 



jp///. 10. The same : square indicating the natural size. 



Fiy. 11. The same: supposed embryonic form, a, prolonged tubular 



aperture ; b, last-formed or upper chambers foraminated; c, lower 



or previously formed ones, fecale l-48th to l-l8(X)th inch. 

 Fig. 12. The same : portion of surface to show the uniform pore-tubula- 



tion of the shell : same scale. Diagram, a, surface-ends of 



three pore-tubes, more magnified, to show the pore in the centre 



respectively : scale l-12th to l-1800th inch. 

 Fig. 13. Carpenteria balanifonms : portion of surface of the shell, to show 



the interrupted pore-tubulation, in contrast to that of fig. 12. a, 



circulai- interstices ; b, reticulated framework ; c, surface-ends of 



three pore-tubes, more magnified, to show the pore in the centre. 



Same scale as the foregoing respectively. 

 Fig. 14. Poli/trema miniaceum, var. album : portion of basal layer, to show 



its commencement from an embryonic chamber in a helical form. 



fl, embiyouic portion ; b, subsequently formed chambers. Scale 



l-24th to 1-1 800th inch. 

 Fig. 15. The same, var. cinnamojnum, showing the same, a, embryonic 



portion ; b, subsequently formed chambers. Scale l-48th to 1- 



1800th inch. 

 Fig. 16. Planorbulina larvata, showing the same, a, embrj'onic portion ; 



b, subsequently formed chambers. Same scale. 



Fig. 17. Planorbulina vulgaris, showing the same, but with the embryonic 

 portion a, outside the planorbuline chambers. 666, planorbiUine 

 chambers ; c c, their cnaracteristic apertures. Same scale. 



Fig. 18. Tinoporus baculafus, var. sphceroidaUs, nat. size. i 



Fig. 19. The same, var. hemispharicus, on a portion of Tubipora musica, 

 nat. 8i:e. 



Fig. 20. The same (spheroidal variety), much magnified, to show: — a, 

 natural surface ; 6, hemispherical section ; c, radiating columns 

 of chambers ; d, incomplete chambers. Diagram. 



Fig. 21. The same : portion of the hemispherical section, more magnified, 

 showing:— a a a, chambers; 6 6, partitions of solid shell-substance; 



c, foraminated or pore-tubulated plates ; d, sides of the chambers 

 pierced by one or more holes of intercameral communication ; e, 

 incomplete chamber. Diagi-am. 



Fig. 22. The same, circumferential ends of three columns in juxtaposi- 

 tion, showing, a, the //(complete chambei", and 6 6, the forami- 

 nated or pore-tubulated complete ones ; coiTespouding with the 

 diagi-am below. 



Fig. 23. Valvnlina ?, textularian, nat. size ; from the specimen of 



Tubipora musica. 



Fig. 24. The same : half of a horizontal or transverse section, seen from 

 within, to show (in the right half only, the other having been 

 left blaJik for convenience) : — a, vertical view of the ends of the 



