TURBINAKLE TABULAT.^:. 63 



Species 45. Turbinaria crassa. (I'l. XXXII. fig. 17.) 



Z)c.scn>/t(«!.— Corallum a thick, horizontal expanse with gradually curved-up margin, the 

 latter wavy and notched. 



Calicles not projecting, scattered, round or elliptical apertures (2 mm.). Septa (18 to 20), 

 not reaching the half-radius circle, sharply differentiated as thin lamellffi from the granular 

 gyrating and interrupted ridges of the ccenenchyma, into which they are continued ; bending 

 down immediately to descend vertically round a large, shallow, elliptical fossa. Columella 

 conspicuous, protuberant, spongy. Interseptal loculi open, wedge-shaped, almost square, not 

 sharply marked off from the furrows of the ccenenchyma. 



On the upper surface, the ccenenchyma is marked by deep, finely gyrating furrows, 

 separated by irregularly granular ridges of about the same width as the furrows. On the under 

 surface, the ridge-and-furrow system is a little coarser ; the furrows, though gyrating, tend 

 mostly to run in the line of growth, the ridges getting thicker and the furrows finer, until, near 

 the margin of the living growth, the latter are merely threadlike, meandering channels in the 

 stony surface of the corallum. 



There is, unfortunately, only one fragment of this type, but it is sufficient to reveal the 

 character of the stock. The margin is thicker than in the last species, and becomes very 

 rapidly of great tliickness, viz. 1 cm. at a distance of 6 cm. from the margin, 1 • 75 cm. at 

 9 cm. from the margin. This very rapid growth in thickness is to be connected with the 

 immersion of the calicles. The broken sections show that the great increase in thickness 

 is above the layer of intercommunication between the polyp-cavities ; the tumed-up ends ot 

 these cavities have accordingly to grow to a great length. This process obviously leads on to 

 the glomerate type of growth. 



A small tubercular upheaval of the ccenenchyma on the upper surface corresponds with 

 a headland in the line separating the living from the dead ccenenchyma on the lower side. 



a. Great Barrier Eeef. Saville-Kent Coll. (Type.) 



Species 46. Turbinaria elegans. (PI. XX. ; PI. XXXII. fig. 18.) 

 ?TurUnaria mesenterina, Milne-Edwards, Los Coralhaires, iii. (1860) p. IGG, pl. E 1, figs, la, lb. 



Description.— CoTaWnm horizontal, dish-shaped, developed on a previous dish-shaped 

 growth. Margin bent and folded, and surface bulged up irregularly. Margin thick. 



Calicles open on thick conical protuberances, the bases of which are generally in contact, 

 so that the ccenenchyma between the calicles appears like a network of narrow valleys. 

 Apertures round or round-oval, of nearly uniform size (2 mm. diameter). Septa about 24, not 

 reaching to the half-radius circle, bending round a deep oval fossa. Columella protuberant, 

 oval, and loosely spongy. The interseptal loculi thick, wedge-shaped or short petaloid, more 

 or less sharply bounded peripherally. 



The ridges of the ccenenchyma are short, thin, erect plates, twisted into all shapes, and 



