12 FOLKE FOLKESON, MADREPORARIÄ. 



The exteriör form of the eorallum resembles that of H elerocyathus aequicostatus 

 E. & H. 



The base is almost rouncl, closely covered with rather large, blunt, shiny grarmlae, 

 and does not show any detachment scar. 



There are one large and some smaller Avormholes in the base, and in no. 3 the 

 trace of a gastropod shell can be seen externally. With the exception of the worm- 

 holes, the surface of the base has no perforations and resembles perfectly that of He- 

 terocyathus aequicostatus E. & H. 



The septa are very thick and quite spongious and ha ve a rough appearance. The 

 primaries oniy seem to have the upper parts of their inner margins entire. There are 

 exactly four cycles; those of the third are the smallest, those of the primary the largest. 

 The septa of the fourth cycle, which rim on either side of a primary septum, are especi- 

 ally high and approach the latter very closely in the exteriör part of the calice; the 

 septa thus form six systems. Near the columella the septa of the fourth cycle join 

 with those of the third. The primary septa decline abruptly down to the columella; the 

 inner margins of the quaternaries are also rather steep; the resting septa slope more 

 gently. There are no pali developed. 



The columella is large and conspicuous (except in no. 3), well delimited, and papil- 

 lous-spongious; in nos. 1, 2, and 3 it is even or slightly convex, in no. -4 concave. The 

 margins of the highest septa about 2 — 3 mm above the top of the columella. 



Distinct costae are lacking, the septa rising directly from the base, at the periphery 

 of which there are very short and shallow furrows, forming the continuations of the 

 interseptal spaces; the stripes between these furrows correspond to costae. 

 All the specimens are quite white. 



Paracyathus porphyreus Alcock 1893 (Figs. 16 — 17). 



Paracyathus porphyreus Alcock 1893 (1), p. 140, plate V, figs. 3, 3 a. 

 45 miles W. S. W. off Cape Jaubert, 15.7.11, 66 feet, 3 sps. 



No. Long dia- Short dia- Depth of Height of Total no. No. of septn, 



meter of meter of calice in eorallum of septa with pali 



calice in mm calice in mm mm in min 



1 ' 7,2 5,8 3 10 48 24 



2 5 4,4 2 6 44 20 



about 

 3 7 C 2,3 8,5 54 



figured. 



With the exception of the dimensions nos. 1 and 2 resemble each other very strik- 

 ingly. No. 3, which was dead and somewhat damaged when collected, shows certain 

 differences from the others. The calice is more open, the long diameter is on a lower 

 plane than the shorter, and the pali have a different complexion, as shown below. This 

 fact, however, can hardly justify the assignment of this specimen to another species than 

 the remaining ones. The species of Paracyathus vary very considerabh", and a crit- 

 ical examination of that genus will certainly prove that many of the specimens which 



