107 



and what seem to be lobes of the columella are in reality the pali of the 

 primaries, which meet in the centre. The same thing occurs in what I 

 call Deltocyathus viola, and I must reserve my remarks on the subject 

 for another occasion. I shall therefore name the species and describe it 

 ae follows : — 



Deltocyathus Aldingensis, n. sp., pi. 1, fig. ] . 



Corallum, hemispherical, or in the form of a truncated cone, or bell- 

 shaped, that is to say, hemispherical, with a very thick cylindrical base 

 like a pedicel, no trace of attachment. Costae very distinct and pro- 

 minent, with numerous small rounded granules, in four cycles correspond- 

 ing to the septa and continuous with them ; primaries and secondaries 

 equal and distinct to the base, where they suddenly thicken; tertiaries 

 thinning out towards the base, and joining the third and fourth orders at 

 about three- fourths from margin, and then making one continuous rib; 

 all very closely covered with numerous small rounded granules. Inter- 

 costal spaces about equal in width to cnstae and having numerous rounded 

 pits or pores in equi-distant series. Calice, circular, either flat or a little 

 convex, from a cauliflower-like mass in the centre arising from the pali. 

 Septa in six systems of four cycles, which are not exsert, of equal thick- 

 ness, very granular, with finely zigzag margins, and continuous with the 

 costae ; primaries straight, free to the centre, where they join rounded 

 cauliflower-like pali ; secondaries also straight and free until about two- 

 thirds from the centre, where they are joined by the tertiaries and become 

 much thicker, and here a kind of paliform excrescence projects. The 

 higher orders unite with the tertiaries about a third from the margin. 

 Dimensions — Alt. of the largest specimens 7, diam. 8|- millimetres. 



The sides of the septa in a section are seen to be very regularly, 

 closely, and prominently granular. A section at the centre shows that 

 all the septa are united by small processes. When the calicular surface 

 is ground flat, the primaries and secondaries are seen to unite in the 

 centre, and the pali (?) are then seen to be represented by a very slight 

 thickening, nothing in proportion to the foliated appearance of the sur- 

 face. The junction is not apparent on the natural surface, but the ter- 

 tiaries seem to send out a transverse thickened process to meet the fourth 

 and fifth orders on each side. It is by a process of this kind that all 

 the septa are joined for they do not in reality curve towards each 

 other. 



Deltocyathus Tateanus, n. sp., pi. 2, fig. 5. 



Corallum, very small discoid, flat, thick in proportion to diameter, 



