120 MADKEPORARIA, 



105. Goniopora Genoa (5)2. 

 [Sassello (Upper Oligocene).] 



Litharcea ponderosa, Sismonda (partim), Pal. Terrain Tert. Piemont (1871), p. 26. 



Description. — Certain Gonioporce from Sassello were grouped with others from Dego as a 

 " species." Believing all such grouping to be premature we return here to the simple facts. 

 The original description applied to this group will be found under the last heading (see p. 35 

 of Introduction). 



106. Goniopora Genoa (5)3. 



[Sassello (Upper Oligocene) ; Geol. Mus. Univ. Rome.] 



Litharcea michelotti (Meneghini in litt.), Angelis, Atti R. Accad. Lincei (5°) i. (1895) p. 180, fig. 9 in 

 text.* 



Description. — Corallum a flat expanding growth ; 7 cm. across and varying from 1 to 

 1 '5 cm. in tliickness ; surface smooth and very slightly wavy. 



The calicles are very uniformly 1"5 mm. across, appear to have been very shallow, 

 crowded, with walls too irregular to be strictly polygonal. The walls simple, incomplete, very 

 irregular, often so wavy that together with the bases of the septa they form a reticulum 

 which is here and there even thick, but only faintly raised above the surface and apparently 

 without any sharp median ridge. 



The septa are short, 12 appear to meet the large columellar tangle. But the typical 

 septal formula of Goniopora is clearly visible, the tertiaries fusing in pairs with the 

 secondaries, but in such a way that it looks as if the secondaries forked near the wall (cf. 

 Diagrams A and B, p. 21). The septa thus appear very wavy and irregular. The interseptal 

 loculi and the spaces in the columellar tangle are large and open, and the whole skeleton 

 is light and porous. 



There is reason to believe that the specimen had been altered by postmortem aqueous 

 action before fossilisation, for the skeletal elements of the surface are thicker than those in the 

 section and the points and projections are smoothly rounded off, as is usual with corroding 

 corals. The specimen has been recently described by Dr. Angelis, and the name given by 

 him was that found on the label in the handwriting of Professor Meneghini. The specimen 

 is particularly interesting because, though it is a Goniopora, the tertiary septa are so small 

 and fuse with the secondaries so near the wall that we have very nearly the condition which 

 we have figured in the Introduction, p. 21. This is not shown in Dr. Angelis' figure, as 

 the method of illustration adopted, which is now very commonly used to illustrate fossil corals, 

 is not adapted for elucidating details of structure. 



* Examination of Dr. Angelis' original preparations, most kindly placed by him at my disposal, 

 shows that the cliches of his figs. 8 and 9 were accidentally transposed by the printers. 



