,30 Prof. P. M. Duncan on the 



lamina?, which terminate either in synapticulie, or in hooked 

 processes with or without endothecal ends. The costte are 

 sliort, subequal or very unequal, having some granulation 

 and a greater or less development of endotheca. Synap- 

 ticulas very numerous between tlie septa near the base, less so 

 higher up ; they occur between the costfB also. Another form 

 shows the bifurcation of costa3 and their union also. The 

 height is S'5 niillim. and breadth 12'5 millim. 



One specimen of P. mamilliformis deviates from the type 

 in being comparatively taller, having a distinct, low, incurved 

 part above the attached base and ending superiorly in a ridge- 

 shaped calicular margin, and in having a very convex calice. 

 The gradations of form and structure from the low and broad 

 types to this high one with such a well-defined convex calice 

 are fairly well seen in the collection. The height of the 

 corallum is 9 miliim., of the calice 6 millim., and the greatest 

 breadth is 12 millim. Some orders of the sixth cycle of septa 

 are present ; there is no sunken central fossula, and the epi- 

 theca is granular. 



Podoseris mamilliformis , Dune, requires some modifica- 

 tion of its original definition, and the following is the correct 

 specific diagnosis : — 



The corallum is simple, attached by a more or less circular 

 flat, or concave base, being very low or slightly raised between 

 the base and the calicular margin, constricted or not, 

 and with costiB. The calice is circular in marginal out- 

 line, slightly or considerably convex, with or without a 

 central fossula. The septa are numerous and become so 

 early in life, are unequal, many long and some uniting 

 and reaching the columella or the fossula, some slender and 

 many rudimentary : longer ones, straight or wavy, ornamented 

 at the arched free upper edge with a single row of large 

 granules. Columella small, mostly formed by the septal 

 ends, and there may be some interseptal structures there, 

 at the base of the fossula, with large granules upon it, or 

 projecting without a fossula. The costae usually more nume- 

 rous than the septa, straight or wavy, uniting and bifurcating, 

 ending in septal laminaj, unequal or alternately very large 

 and small, with granules. The septo-costal number is from 

 less than complete five cycles to five cycles with part of a 

 sixth. Synapticulffi moderate in number, continuous with a 

 series of ridges placed obliquely upon the flanks of the septa ; 

 but the ridges may be curved, so as to resemble hooked pro- 

 cesses in section, and may be free at one end or terminate in 

 a thin endothecal process. Endotheca scanty, may exist 



