llyclractinia, Parkeria, and Stroraatopora. 75 



Fig. 10. The same. Loug^itud'uuil section of a tube ma^itied, showing 

 tiie " anmiliition ;" a, tranvorso yeetinu to sliow the diaphrag- 

 matic form of tiio constrictidu, with hole in the centre. 



Fitj. 11. Jli/dracliniti Vicdri/i, u. sp. (fossil), nat. size. Portion of natural 

 surface, showing : — a, large spines ; b, circular area, to which tho 

 apertures of tho surface are added j all the rest having bueu 

 omitted for perspicuity. 



Fiff. 12. The same. Ca.st of tube, showing anmdations. a, cylindrical 

 form of the cavity in which the cast (i) is found. 



Fig. 13. I'arfuria xplHcrica. Vertical section, natural size, a, infil- 

 trated or consolidated zone or shell ; b, semi-inliltrated zone ; c, 

 joMutiltrated portion, or kernel ; </, the first six lamina) of c, 

 delineated to show intervals traversed vexlically bv the radiating 

 tubes ; the innermost ellipticiU, at one end of wiiich the dark 

 portion represents a cavity iu which probably there was some 

 Kind of foreign body. 



Fig. 14. The same. Diagram of tissue-fibre, magnified to show its re- 

 ticulated, anastomosing, contorted arrangement and its composi- 

 tion, a, fibre, composed of colourless transparent calcspar ; b, 

 coating or incrustation, composed of granular, crystalline, yellow- 

 ish calcite. 



Fig. 15. The same. Diagi-am of portion of surface of kernel (fig. \?>, c), 

 showing : — a, ends of radiating pillars of tissue-fibre ; b, circular 

 area, to which the ends of the radiating tubes are added. Natu- 

 ral size. 



Fig. IG. The same. Diagram of portion of natural siu'face of a specimen 

 lA inch in diameter, showing : — a, ends of radiating pillars of 

 tissue-fibre ; b, circuljir area, to which the ends of the radiating 

 tubes are added. Natural size. 



Fig. 17. The same. Vertical section, natiiral size, a, circle indicating 

 size of specimen ; b, the first six laminae, delineated to show 

 intervals travereed vertically by the radiating tubes ; c, foreign 

 nucleus, consisting of a fragment of a Nautiloid test. 



Fig. 18. Loftusia persica, Brady. I'ortion of natui-al surface, natural 

 size, a, papilliform apertural eminences of radial tubes; b, 

 boss-like eminence, presenting, c, a trace of branched lines across 

 (I-* radiating) from the simimit. 



Fig. 19. Stromatupora with bossed sui'face, in black-grey Devonian 

 limestone. In the possession of Mr. Vicary. Portion of natm'al 

 surface, natural size, a a a, bosses presenting the " stellate 

 system of canals " respectively on the summit ; b, papillary aper- 

 tures of radial tubes. 



Fig. 20. Strvmatopora in grey Devonian limestone, submfiltrated. In the 

 possession of Mr. Vicary. Diagram of horizontal section, na- 

 tural size, fl, stellate systems of canals ; b, ends of radiating 

 tuljes. 



Fig. 21. The same. Horizontal section of ends of radiating tubes, magni- 

 fied, to show intertubular communication like that of Syringo- 

 pora : a, longitudinal section of tube, to show diaphragmatic 

 lines and appearance of annulation ; b, intertubular communi- 

 cations. 



Fig. 22, Strumatopora (Sgn'tigoporn), in grey Devonian limestone. In the 

 possession of Mr. \'icary. Nearly horizontal section, natural 

 size, fl, stellate system of canals ; b, ends of the radiating tubes, 

 much larger than in the foregoing instance. 



Fig. 23. Tho same. Section of radiating tube, magnified, to show the dia- 

 phragmatic lines of amiulation cut obliquely. 



