CA R YOPH YLLIA CEA . TURBINOLIA DM. 



THE SMOOTH-RIBBED WEDGE-COEAL. 



Sphenotrochus Macandrewanus. 



Plate X. Fig. 4. 



Specific Character. Corallum uniformly diminishing downward; ribs 

 smooth, not salient ; edge of calice plane. 



Twbinolia milletiana. Thompson, Annals N. H. Ser. 1. xviii. 394. 



Johnston, Br. Zooph. Ed. 2, i. 196 ; pi. 



xxxv. figs. 1—3. E. P. Wright, N. H. 



Rev. vi. 122. Gosse, Man. Mar. Zool. i. 



32 ; fig. 49. 

 Sphenotrochus Andrewianus. M. Edwards and Haime, Ann. d. Sci. Nat. 



Ser. 3. ix. 243 ; pi. vii. fig. 4. 

 Macandrewanus. M. Edwards, Hist, des Corall. ii. 70. 



■ GENERAL DESCRIPTION. 



Corallum. An inverted cone, compressed, lengthened, straight, with 

 the inferior extremity forming a wedge-like blunt point. 



Ribs. Perfectly straight, smooth, nearly equal throughout, or slightly 

 enlarged above, separated by intercostal spaces about twice as wide as 

 themselves, moderately prominent, continued round the edge of the scar 

 where the corallum was originally attached. 



Calice. The edges on the same horizontal plane ; outline elliptical, in 

 the ratio of 100 : 120. 



Plates. Twenty-four ; in three complete and well-developed cycles, 

 close-set, straight, thick at the margin, and gradually thinning towards the 

 centre of the calice ; salient, arched at their upper edge, with a surface very 

 slightly granulose. The primaries and secondaries are subequal and similar* 

 and hence the appearance of twelve systems ; each of these is united with 

 the columella by two diverging laminse, as if the plate were split at its inner 

 edge, and the two halves separated. 



Columella. A single, thin, vertical lamina. 



Size. 

 Height half an inch ; diameter of calice one-fourth of an inch by one-fifth. 



