BY W. N. BENSON, 



^77 



inose witli the primaries. The dissepimeiitul stnietiires are limited 

 in number and irregular (^'"c Te<t-fis'.4). There is no Australian 

 Cyathophylloid of this type hitherto described. The specific 

 characters are the sparse de- x'^^^Si^^'^ 



velopment of dissepimental 

 tissue, the steroplasmic layer ,^^\^ 

 on all septa being developed 

 to a rather abnormal extent." 



Text-fig. 4. 



rraiisverse section of Cyal]iOphullnm sp. 



iiov.. ( X 2), Looniherah Limestone. 



'■''S'pon<.io2)hjjlhim, (?) sp.nov. 

 — An aberrant type of S'pou- 

 yopJiyllnm, in which the 

 structure of the corallite-wall 

 is masked, its place being- 

 taken by dense vesicular tis- 

 sue. (8ee PI. XXXV., figs. 2 and 

 ?u and Text-fig.5). The septa 

 are more persistc^nt than in 



other Australian Spongophylloids, and, in most cases, spring from 

 the replaced wall, there being a space of ai^out omm. of vesicular 

 tissue separating the se[)t;il ends of adjoining corjUHtes, Dissepi- 

 mental tissues are dense, and the \esicles are small. The septa in 

 tlie central area are 24-:i0 in number. To the naked eye, this 

 remarkable coral has the general appearance of a l'hi/li]jsastrcca 

 hut, under the lens, the septa are seen to be non-contluent. The 

 absence of a true wall ma}^ not necessarily separate it from the 

 Spongophyllums, as specimens of the typical S. biparlUa from the 

 Silurian of Yass, have, in some cases, a portion of the corallite- 

 wall undeveloi^ed. It is even possible that this may represent a 

 stage l)etween Spornjojili/fUum (sensu stricto), and Endophylhim.'' 



[A recent statement by Dr. S. Smitli appears to illustrate this 

 remark (21) — "Among the Rugose colonial corals there are cer- 

 tain genera, or certain species within a genus, in which the eoral- 

 lites have lost their epitheca, and are united by their dissepimental 

 tissue. The septa of adjacent corallites in the astraeiform colony 

 tend to become confluent, but all stages of this development, from 



