186 Mr. P. M. Duncan on some Fossil Corals. 



terns, is as abnormal as the Echidna hystrix, as far as European 

 classifications are concerned. The new genus must be placed in 

 the neighbourhood of Axosmilia ; and it connects the families 

 of the Turbinolides and the Astraeides. 



The connexion between the septal and costal arrangements in 

 the species of the genus is very remarkable. The bases of the 

 septa and of the costae are not continuous, but the septa appear 

 to correspond with the line of depression between the costae. 

 This is common in species of other genera in Australia, but is 

 very rare indeed in any specimens from any other part of the 

 world. It was noticed in the c Annals' of September 1864 in 

 Flabellum Victoria, nobis, and the arrangement is seen in the 

 two species of Sphenotrochus described in this communication. 

 It gives a sort of Australian stamp to the corals. The costae 

 are much broader than the septa ; and it will be observed that 

 in Sphenotrochus emarciatus the line of depression between the 

 costae is continuous with the line which separates the two laminae 

 of which the septa are composed. The costae to the left and 

 right of the depressed line give each a root to the septum. The 

 species of the new genus are readily distinguished. 



The Sphenotrochi are at first sight not unlike well-known 

 European older Pliocene and recent forms; but the emarciate 

 base and appendages, with the direction of the plain costae, and 

 the septal arrangements, distinguish the Australian species, and 

 prevent their being confounded with the genus Platytrochus. 



The cyclolitoid Antillia is a most interesting species. The 

 genus superseded Montlivaltia during the Miocene (it is a 

 Montlivaltia with a well-formed columella); and it would appear 

 that all the various forms of the elder genus are represented in 

 the more modern. The tall cylindro-turbinate, the shorter, the 

 forms with oval, elliptical, or circular calices, those with large 

 bases and short or tall sides, and those with many or but few 

 septa, amongst the Montlivaltice, are represented in the Miocene 

 of San Domingo, Guadeloupe, Jamaica, and Sinde by Antillice of 

 corresponding shape. In the Hamilton Tertiaries the interesting 

 cyclolitoid Montlivaltice of the Oolites have a representative in 

 the Antillia lens. 



EXPLANATION OF PLATE VIII. 



Fig. I. Sphenotrochus australis: a, lower half, natural size; b, part of 



calice and columella, magnified 4 diams.; c, transverse section, 



magn. 4 diams. ; d, costae, magn. 2 diams. 

 Fig. 2. Sphenotrochus emarciatus : a, nat.size; b, side view, magn. 4 diams.; 



c, calice, magn. 6 diams.; d, continuation of septa and intercostal 



lines, magn. <> diams. 

 Fig. 3. Conosmi/ia elegans : a, nat. size; b, side view, magn. 3 diams,; 



c, calice, magn. (> diams, 



