150 MADREPORAEIA. 



Specimen No. 11. Is a pear-shaped knob, detached from its pebble. The calicles are 

 typical in shape, but larger (5 mm.) and shallower, and the wall lower and not so sharp. 

 The skeletal elements are very delicate. Geol. Dept. 48335. 



Specimen No. 12. Seems to be a fragment of a similar pear-shaped stock, broken down 

 the middle. The outer surface is worn. The inner shows a complete vertical section. The 

 skeletal elements are thin, as in No. 11. The septa, seen in vertical section, are very thin and 

 laminate, the lamina? being strengthened by rows of echinulse or slight ridges slanting upwards 

 towards the axis.* They are very irregularly perforated, the pores often in groups, sometimes 

 very scattered, at others so close as to make a lattice-work. The septa, in one and the same 

 calicle, vary in width and consequently the columellar tangle which involves their ragged 

 edges varies also in size. Geol. Dept. 48335. 



Specimen No. 13. A small fragment perhaps of the same, but shows the lower edge of 

 such a colony with the calicles all dragged out of shape, and the septa running from calicle to 

 calicle. Geol. Dept. 48335. 



Specimen No. 14. A good sized fragment of a large ovoid mass, bored by Gastrochcena. 

 Its core has been impregnated with iron ; the surface has been abrased. The wall-reticuhun 

 is open and the elements thin in the sections. On parts of the surface the septa and the 

 wall-elements seem to become thicker and more flaky, but this may be the result of post- 

 mortem aqueous action. Geol. Dept. 48337. 



In the following the septa mostly thicken towards the wall, as described by Milne- 

 Edwards and Haime ; the threads of the wall itself are irregularly thickened or nodulated, 

 and are either single or form a reticulum which may be flaky and dense, with small pores 

 like worm borings. 



Specimen No. 15. A nearly globular mass which seems to have begun on the upturned 

 edge of a flat pebble, and then to have partially rolled over. The calicles are of the typical 

 shape, about 3 - 5 mm., but the wall-ridge is blunt. In the vertical section the septa are almost 

 all very open lattice-work, a fact which may be correlated with greater thickness of the wall- 

 elements. Geol. Dept. 48487. 



Specimen No. 16. A small nearly spherical colony upon a very small pebble. Calicles 

 small, the largest 3 ■ 5 mm., of the typical shape, with nearly straight wall-threads, and a 

 certain number of primaries and secondaries rising directly from the thread in a very con- 

 spicuous manner. In the sections the septa are lattice-like, and the wall-reticulum, where 

 developed, is as if composed of twisted flakes. Geol. Dept. 49575. 



Specimen No. 17. A small colony encrusting a valve of Area biangula. Calicles about 

 3 mm., rather deep and concave than shallow funnel-shaped, with the wall-ridges blunt and 

 reticular (? abrased). The reticulum of slightly coarser texture than the septa. 



Geol. Dept. 48335. 



Specimens Nos. 18 and 19. Two nearly globular or ovoid specimens, showing varying 

 degrees of abrasion. Here and there shallow funnel-shaped calicles with low sharp walls may 



* In Lonsdale's figure 5 d the strias are figured either horizontal or sloping downwards (Dixon's 

 ' Sussex,' pi. i.). Cf. Duncan's ' British Fossil Corals,' pi. iii. fig. 4, where this point is correct, but 

 the wall is quite misrepresented. 



