92 BRITISH PALAHOZOIC FOSSILS. [Zooruyra, 
sulci, obscurely disposed in pairs, six in two lines, with numerous scattered, irregularly placed spinose 
tubercles. 
I have not seen the internal structure of this species, but as it has clearly no distinct axis, I cannot, with 
M. Michelin, refer it to the genus Cyathaxonia, and have no hesitation in placing it in the present genus, from 
Koninck’s figure. 
Position and Locality —Rare in the black carboniferous shale, Poolwash, Isle of Man. 
Genus. AMPLEXUS. See page 70. 
AMPLEXUS CORALLOIDES (Sow.) 
Ref. and Syn.—Min. Con. t. 72.= A. Sowerbyi. Phil. Geol. York. t. 2. f. 24. 
Sp. Ch.—Corallum cylindrical, or slightly compressed, long, tortuous, very slowly tapering; extreme 
young, slender, irregularly flexuous, and with small irregular distant transverse wrinkles, crossed by faint 
longitudinal striae, double the number of the marginal lamell:e; adult surface nearly even, marked with fine 
close transverse wrinkles, or strise, and faintly marked longitudinally by the lamellar strize; marginal lamelle 
forty-four to forty-six at the diameters of nine to fourteen lines, very short, strong, resting on the deflected 
edges of the diaphragms, across which faint strie proceed (? membranous continuation of the lamellee) towards 
the centre ; diaphragms strong, numerous, slightly undulated. 
There is often a Caninia-like depression towards the margin of certain of the diaphragms, but it is not a 
true siphon, is never perforated, and does not correspond in position with a similar depression on the adjoining 
diaphragms. A young specimen, three lines in diameter, has got twenty-three marginal lamellee. The ordinary 
adult diameter is about one inch three lines, at which size the corallum is nearly straight, or slightly curved, 
cylindrical, and tolerably even ; the lamellar sulci of the surface measuring two to three spaces in two lines. 
Position and Locality—Common in the carboniferous limestone of Derbyshire. 
Genus. COLUMNARIA (Gold.) redefined. 
Gen. Char.—Corallum of aggregated subparallel branches, either round and concentrically wrinkled, or more 
usually, by mutual pressure becoming polygonal and longitudinally sulcated, but always easily separable ; 
internal structure as in Amplexus, having many transverse simple diaphragms, and the walls longitudinally 
suleated by marginal rudimentary lamell, which crenulate the edges of the transverse plates. Increase by 
fissure of the parent tube, or cell, as in Stylastraa (Lonsd.) ‘Type of the Genus Columnaria sulcata (Gold.) 
This genus has been erroneously described by Goldfuss in the first instance, and has been misunderstood by 
nearly every subsequent author—all describing radiating lamelle from the walls to the centre, and stating 
that there are no transverse plates ; I was rather surprised, therefore, to find the characters I have given above 
in authentic specimens from the Eifel of the C. sulcata (Gold.) ; they also exist in the C. irregularis (Miinst.), 
C. senilis (Koninck), and the following. I deny the existence in those species of radiating lamellz near the 
centre, and find the transverse diaphragms conspicuous. The real affinities of the genus seem to be between 
Michelinea and Amplexus, differing from the former in the tubes being individually distinct (as in Stylastrwa), 
and easily separable by fracture, and being without communicating pores; from the latter it only differs in 
its compound mode of growth. As thus restricted the genus is, no doubt, a good one: the other dissimilar 
species, placed in this genus by Dr Goldfuss and others, will easily fall into Cyathophyllum and other existing 
genera. 
CoLUMNARIA LAXA (M°Coy). PI. 3. C. fig. 11. 
Ref.—M°Coy, Ann. Nat. Hist. 2nd Series, Vol. IIT. p. 122. 
Sp. Ch—Corallum forming large masses of contiguous, slightly flexuous tubes, rarely in contact ; generally 
round, and finely wrinkled transversely, occasionally the tubes in some part of their length touch the adjoining 
ones, and then become polygonal and longitudinally suleated ; transverse diaphragms undulated, and obliquely 
inclined in various directions ; diameter of tubes from three to four lines. 
