306 THE PROCEEDINGS OF THE LINNEAN SOCIETY 



This singular coral is not unlike Paracyathus Thulensis, Gosse, 

 except that it has only three cycles. Set in the base of a Lunulites 

 it makes the conical polyzoary not unlike a complete Turbinolian, 

 but the calice does not fill up the whole of the base, and is not 

 usually symetrically placed. 



Oenus Deltoctathus. M. Edw. 8f H., 1848. 



Corallum free and without trace of adherence, calice shallow, 

 columella pluripartite ; pali entire, highly developed, principally 

 those of the penultimate cycle which is directed towards the anti- 

 penultimate so as to form chevrons or deltas. There are none 

 before the last cycles. Costa? granular and distinct to the base. 



Deltoctathus italicus. M. Edw. 8f H. 



Corallum a short cone ; calice circular ; septa very slightly 

 exsert, thickened exteriorly, of four complete cycles and six 

 systems ; columella fascicular ; pali thick and very unequal ; 

 costge in cycles regular and granular. This occurs fossil in the 

 Italian Miocene, and still exists in the Carribean Sea. It is not 

 uncommon in the Geelong aud Cape Otway beds, but has not been 

 found at the Muddy Creek, Mount Gambier, or in Tasmania. 



Deltoctathus viola. Woods & Duncan. 



This species was long mistaken for a Garyophyllia, because 

 when worn the deltoid pali became eroded, looking like a single 

 circle before the tertiaries. I have described and figured a 

 perfect specimen in the Proc. Boy. Society, N. S. Wales, 1877. 



Deltoctathus rot^formis. n. s., PI. 5, Fig. 2, a & b 



Corallum circular, depressed, with perfectly flat base which is 

 coarsely granular and so thin that it is frequently worn through 

 and shows the radiating septa; calice circular in outline, fossa very 

 slightly sunk ; septa in six systems of three cycles ; primary 

 and secondary equal but the former much more exsert and pro- 

 jecting high above the calice ; tertiary short and without pali. 

 All granular ; pali united to the inner edges of the first and 

 second cycles and throwing out thick transverse processes at their 

 junction. Columella papillary ; granules of the base vermicular 



