I20 



Genus DUNCAN I A, Pourtales.* 



There is only a single perfect specimen of this genus in the 

 collection. It was broken off its narrow attached base by the 

 trawl, but before this its cavity near the base had become quite 

 solid, filled in by corallum. 



In the British Museum Collection, I found a single specimen 

 of D. barbadensis, Pourtales, which evidently had been sent 

 by Pourtales hmiself to Duncan, or Moseley. It was not in 

 good condition, but showed signs of the regular hexameral ar- 

 rangement. Neither theca nor epitheca were distinguishable, 

 distinct from one another. There was a simple wall to the 

 cahcle, outside which the tissues did not extend. The tissue, 

 which forms a theca, arises by an uprising of that depositing 

 the basal plate, while that building up an epitheca is the side 

 wall of the polyp. The wall therefore of the calicle of Dun- 

 cania is an epitheca. The interseptal chambers or the interior 

 of a cahcle may be filled in by solid corallum (stereoplasma), 

 deposited by the tissues, but any deposition without the forma- 

 tion of tabulae or dissepiments is not a character of any import- 

 ance in the TurbinoHdae, nor, so far as I am at present aware, in 

 Madreporaria. 



One of the characters then on which Pourtales founded the 

 genus Duncania, and both the characters which Duncan gave 

 for his alliance Haplophylloida, I can only regard as quite 

 worthless in the genus under consideration. Whether it be 

 really distinct from certain other genera in the Turbinoloida, 

 with which it should be placed, I cannot at present express an 

 opinion. It is almost certainly identical with Haplophyllia, 

 which was also described by Pourtales. The only difference 

 lies in the columella, which in the latter genus is described as 

 being " styliform, strong, very thick at the base," while the 

 Duncania type has a " multipillared columella," and the present 

 q:>ecimen is intermediate. 



14. DUNCANIA CAPENSIS, n. sp. (PI. I., figs. 6 a-c.) 



Corallum cylindrical, with widely open, rounded calicle. Wall 

 a thick epitheca, with a tendency to shghtly constrict at the 

 mouth, worn away below showing fine longitudinal lines, de- 

 pressions opposite the attached edges of the septa. 



Septa 48, in four cycles, I. to III. meeting in the centre of the 

 calicle. Primaries and secondaries sub-equal, with their upper 

 edges rising i to 2 mm. above the upper edge of the epitheca, 

 rounded above, but with smooth edges, save for a single fine 

 paliform tooth to each where it runs in to join the columella, 



* Zool. Results of Hasslar Exped., 1874, P- 44- 



