1848.] LONSDALE ON FOSSIL ZOOPHYTES. 1).') 



state was not observed. Supposed early but mature conditions 

 (fig. 17) exhibited round, sometimes slightly raised tubular termi- 

 nations, which opened in the same plane with that of the general 

 surface ; and when arranged transversely, they in general constituted 

 well-marked ridges. The longitudinal ribs also scarcely projected 

 (fig. 18). The secondary apertures varied in form, likewise in size 

 and distinctness ; and their margins were depressed or inclined in- 

 wards*. A presumed somewhat older state had a rougher surface 

 in consequence of increased boldness in the framework of the reticu- 

 lation ; while the tubular openings were depressed rather than raised, 

 and the transverse row^s did not form ridges : in an apparently still 

 older fragment the rugosity of the exterior was much greater, the 

 major apertures were irregular in outline, and the minor diminished 

 in size ; the network was also obliterated : lastly, in what was con- 

 sidered an aged condition the mouths of the tubes were often in- 

 distinct, and the secondary pores were reduced to punctures in rugose 

 projections. The changes on the reverse side agreed completely with 

 those just mentioned, so far as concerned the network. 



Transverse sections (fig. 21) presented a tubular area, and an ex- 

 terior opake zone, in which could be detected occasionally the out- 

 ward range of the visceral tubes ; also horizontally-intersected minute 

 tubuli, which in two cases apparently ranged from the surface-net- 

 work to an abdominal hollow. The internal vertical composition, so 

 far as respected the tubes, was tolerably shown in two translucent 

 slices (fig. 20) . Those cavities, as before stated, had a considerable 

 extension, the inferior termination being generally in the axis of the 

 branch. Their area was invariabl}^ clouded by peripheral structures, 

 in which very minute bright specks could be detected ; and occasion- 

 ally a larger circle, believed to be one extremity of the slender, hori- 

 zontal tubuli just mentioned ; but not a trace was discovered of a 

 transverse lamina indicative of the digestive organs having changed 

 their position. Betw^een the walls of adjacent tubes was very often a 

 fine line similar to that mentioned in the notice on Choristopetaliim 

 impar ; but in some cases it was evidently an early condition of a 

 young cavity, as it gradually expanded upwards, and assumed the 

 characters of a mature state ; while in others less clear, it appeared 

 to mark a structural separation between the walls, being more or less 

 continuous without any increase in width. The nature of the reti- 

 culated zone was ascertainable only in fragments purposely abraded 

 to different depths, and even then the detection of the characters 

 required care. A small portion of a branch slightly rubbed down 

 presented obliquely exposed visceral cavities, with minor opake circles 

 generally in contact, but sometimes with a faint indication of a sepa- 

 rating paler line, the circles clearly representing the secondary surface- 

 apertures. Another fragment (fig. 22), more deeply w^orn, exhibited 

 in the middle longitudinally exposed tubes, but at the sides and upper 

 extremity of the branch, w^here less had been removed, large ovals 



* A Slianklin specimen, obligingly lent the author by Mr. Morris, afforded per- 

 fectly similar characters. For a notice of the existence of the coral at that locality, 

 consult Dr. Fitton's Memoir, p. 318 o/?. cit. 



