50 MADREPORAEIA. 



B. Foliate, with under sides of fronds most conspicuous. 



g. Shark's Bay (with T. coTispicua). Saville-Kent Coll. 



/(. Shark's Bay (with T. conspicua). SaviUe-Kent Coll. 

 (This latter (A) ought perhaps to be classed separately. ) 



C. Encrusting masses, throwing up massive cylinders or protuberances (Plate XV.) 



i,j. Shark's Bay. Saville-Kent Coll. 



D. A single fragment of a cylinder forming at the top a gracefully gyrating frond. 



k Shark's Bay. Saville-Kent Coll. 



E. Irregular masses of fronds, thin finger-like processes, &c. 



I, m. Shark's Bay, West Australia. Saville-Kent Coll. 



E. Two fragments of fronds which may belong here. 



n. Green Island, Great Barrier Eeef. Saville-Kent Coll. 



0. Great Barrier Eeef. Saville-Kent Coll. 



G. Two large cups which, from the character of the calicles, may be young specimens of 

 T. magna, not yet showing the irregular growth. 



2}. Great Barrier Eeef. Saville-Kent CoU. 



q. Port Denison, Queensland. Saville-Kent ColL 



n. A large stalked cup, with edges thrown up into great folds, showing the method of 

 modification of the early cup stage. (Plate XIV.) 



r. Gulf of Carpentaria. Saville-Kent CoU. 



Species 28. Turbinaria irregularis. (PI. XII. ; PI. XXXII. fig. 4.) 



Description. — Corallum a mass of gyi-ating fronds, wrinkled on the outside, seldom more 

 than 5-6 cm. deep. Hence the stock does not tower like the last. The fronds frequently fuse 

 face to face, the under sides being the more conspicuous, forming open funnels and valleys. 

 The stock may also form encrusting masses with protuberances and cylinders. 



The calicles, round and small (apertures 1 • 5 mm.) and inconspicuous on the fronds, large 

 (3 mm.) and projecting on the protuberances. The septa (ca. 18 in the smaU, 28 to 30 in the 

 large calicles) are conspicuous, although^^at the aperture they do not reach the half-racUus circle. 

 They commence almost at once to descend round a large circular fossa, curving inwards near 

 the bottom towards the spongy columella. This is mostly flat or even concave, in which case 

 the fossa is like a deep bowl. 



The interseptal loculi very inconspicuous round the margin of the calicles, but show as 

 deep oval holes all round the columella. 



The coenenchyma is spongy or reticulate on both upper and lower surfaces, without any 



