CA R YOPR YLLIA CEA . 



TURBINOLIADJ'J. 



THE KNOTTED WEDGE-COEAL. 



Sphenotrochus Wrightii. 



Plate X. Fig. 3. 



Specific Character. Corallum pedicellate, with swelling nodes; ribs 

 papuliferous on the body, and crossed with zig-zag folds on the pedicel. 



Sphenotrochus Wrightii. Gosse, Nat. Hist. Review, vi. 161 ; pi. xvii. 

 figs. 1—4. 



GENERAL DESCRIPTION. 



Corallum. Simple, straight (or else with the base considerably curved 

 laterally), compressed above (the axes of the disk being 60 : 42 in general ; 

 in one example, however, 60 : 50), but rounded in the lower two-thirds, 

 pedicellate; the body and the pedicel varying exceedingly in their rela- 

 tive proportions, the former being to the latter as 1 : 5 in one example ; 

 in another, as 1 : 1; in another, as 1 : 1'2, — no two of the four specimens 

 in my possession being alike in tliis respect. The pedicel is surrounded 

 by four to six constrictions, varying greatly in their relative distance : 

 these separate nodes are more or less swollen, of which one, a little above 

 the base, is usually more ventricose than the rest; the pedicel generally 

 enlarges upwards, but its distinction from the body ia marked by an 

 abrupt shoulder. 



Bibs. About as wide as the interspacss, distinctly traceable only as far 

 down as the termination of the body ; their course is irregularly angular ; 

 the primaries and secondaries terminate at the shoulder in 

 prominent knobs. On the pedicel only the six primaries are 

 distinguishable, and these are then crossed by numerous 

 strongly indented zig-zag folds, of which the higher angle 

 is on the rib, the lower in the interspace. All the ribs of 

 the body-region aro'studded with irregularly projecting points 

 or papillary eminences. 



Base. A small but distinct circular cavity, into which the 

 extremities of the six primary ribs project. 



Calicc. Considerably arched, the short axis being much 

 the higher ; rather deep. 



Plates. Twenty -four, in three cycles ; the lateral primaries 

 and secondaries more developed than the terminal ones ; moderately close- 

 Bet, irregularly bent in their planes, thick exteriorly, suddenly diminishing 



s. WRIGHTII 

 (magnified). 



