ITALIAN GONIOPORA. 121 



107. Goniopora Genoa (5 )4. 

 [Dego (Upper Oligocene), coll. Michelotti ; Geol. Mus. Univ. Rome.] 

 Rhodarxa ambigua, Angelis, Atti R. Accad. Lincei, i. (1895) p. 181 (text fig. 8).* 



Description. — Corallum massive, complete form unknown, there being only a single 

 pebble-shaped specimen with calicles much obscured. 



Calicles all sizes owing to intercalicular budding, up to 7 mm. Septa about 24, thin and 

 straight near the walls, but greatly interrupted by perforations, and also much bent near the 

 axis (the hook-like curl in the figure is certainly delusive). The formula is difficult to 

 make out ; traces only of the typical arrangement can be seen in the section, but I have failed 

 to find any symmetry in the calicles exposed at the surface. The columellar tangle seems to 

 have been very irregular, with a good many angular nodules. 



The section of tins coral (prepared by Dr. Angelis and kindly lent me for examination) shows 

 that it is a true Goniopora. One of the chief points of interest are the large calicles. 



There is only one specimen from this locality in the British Museum Collection which 

 might possibly be identified with the above. It looks like a Poritid, but is now so altered 

 internally that the sections show no trace of structure. 



a. Geol. Dept. R. 3642. 



108. Goniopora Genoa (5)5. 

 [Dego (Upper Oligocene), coll. Michelotti ; Geol. Mus. Univ. Rome.J 

 Litharma pulvinala (partim), Angelis {rum Michelotti f), Atti R. Accad. Lincei, i. (1895) p. 179. 



Description. — Corallum a thin, nearly circular plate with very sharp edges, closely 

 encrusting, upper surface slightly wavy and convex. 



Calicles about 2 mm. across and less, depressed, with raised blunt but well-marked walls. 

 The walls are mostly simple threads and appear thickened where the septa abut against them 

 close to their margins ; here and there, however, they form a few independent reticular meshes, 

 e.<T. in raised angles where new buds would have formed. The general appearance of the 

 septal formula is not unlike that drawn by Michelin for his P. collegniana (Icones, pi. 13, 

 fief. 9 ; see also above, p. 117), but close examination shows quite clearly the typical formula, 

 the tertiaries being short and bending quickly round to fuse with the secondaries. In the 

 smaller calicles parts of this formula are confused. The epitheca is wrinkled, except where it 

 was closely adherent to the substratum. The meeting of septa in the centre is very irregular 

 so that no conspicuous columellar tangle is formed. There appears at times a prolongation 

 of a septum like a directive. 



The specimen to which this description applies is one of those referred to by Dr. Angelis, 

 and was kindly lent by Professor Portis for examination. It belongs to the Michelotti Collection 



* See footnote on the preceding page. 



t Etudes Miocene Infer. (1861), p. 158, pi. xv. figs. 3 and 4. 



R 



