62 MADREPORAEIA. 



cular junctions more delicate than the septa. In the lateral calicles the wall is thickened by 

 an extra row of septal granules one on each side of the median ridge, the latter showing traces 

 of points joined by a delicate zigzag thread. The three cycles of septa, nearly equally 

 developed round the margin, are rows of stout rough granules, which usually descend steeply 

 and then curve round towards the large columella, which consists of a tangle of flakes and 

 looks nearly solid. The typical formula can be made out, but the points of fusion of the 

 septa are imbedded in the columellar tangle. Scattered granules rise from the surface of this 

 latter, and here and there group themselves roughly into a rosette, occasionally with a central 

 knob in line with the directives. 



This coral, which was developing upon a dead Turbinarian, seems to form a transition 

 between that last described and the next following. The walls are slightly steeper, thus 

 making the colony convex instead of flat and explanate, but otherwise the calicles seem to 

 be built on the same plan, the septa having similar granular edges and similarly running up 

 the walls, only here delicate synapticulre form a zigzag line. At the edges of the stock the 

 rows of septal granules run over the walls and out to the edge of the epitheca. 



a. Zool. Dept. 92. 1. 16. 25. 



Presented by the Lords of the Admiralty. 



31. Goniopora North-West Australia (6)5. 

 [Holothuria Bank (15 fathoms), coll. Bassett-Smith ; British Museum.] 



Description. — Corallum massive, with smooth convex surface, edge closely encrusting and 

 not bending down far. 



Calicles large, variable in size (up to 4*5 mm.), deep 2*5 mm., but open, angular, and with 

 broad flat floor, on to which the septa slightly slope. The wall has a stout rough edge, com- 

 posed of the granular tops of the septa, which are usually irregularly united, but frequently 

 form a single row, even in the lateral calicles. The 24 septa, all equal in size round the 

 margin, are straight rows of stout rough granules which descend with a slight slope (or else 

 straight with a concave curve at the bottom) to the columellar tangle. The points of fusion of 

 the septa are all involved in the immense columella, which seems to be composed of large flat 

 flakes with wavy and slightly curled edges. Small scattered granules, or else the turned up 

 edges of thin flakes, are here and there arranged into a radial rosette, which though almost 

 everywhere seen in traces is nowhere really pronounced. 



This coral is unfortunately not a very good specimen. It was evidently growing con- 

 tinuously with a rather shapeless fragment of a former growth which had suffered from foreign 

 organisms. It seems to carry on the series in which the last two corals are stages. The stock 

 is still more convex and the calicles deeper, that is, have higher walls, and the central rosette 

 is less conspicuous. All three are united by the sizes of the calicles, by the type of internal 

 skeleton, and by the symmetrical septa whose top edges are broken up into rows of 



