256 Chrktmas Island, 



0. andrewsiana is a very striking form in the Christmas Island 

 limestones. The test is very thick in the centre, thinning off 

 rapidly to a peripheral flange of some extent. In general 

 contour it may be compared with Orbitoides {DiscocycUna) 

 applanata, Giimbel.^ The chambers of the median plane are of 

 the Lepidocycline character, and more rounded and crowded 

 with one another than in some of the other forms of Orlitoides 

 present in the same limestones. The chamberlets of the exterior 

 are roughly discoidal and flattened, so that a tangential section 

 affords a view of the chamberlets as large circular perforations, 

 which is a marked feature in the sections. Many of the specimens 

 noted are megalospheric. The internal structure of 0. andrewsiana 

 generally resembles 0. sumatrensis, but the former is much larger, 

 and has a very extensive peripheral flange. Average diameter 

 finch (9'375 mm.). Common. 



Orlitoides {Lepidocyclind) insul(S-natalis, sp. nov. Common. 

 (PL XXI, Fig. 13.) 



0. (Z.) ephippioides, sp. nov. Common. (PI. XXI, Fig. 15.) 

 0. (Z.) verheeJci, I^ewton & Holland. One specimen. 



Limestones feom Plateau and Hills. 



No. 143. Edge of cliff. South Point Hill, 1,020 feet. 



A finely crystalline and calcareous rock, in which the organisms 

 are almost entirely obliterated. A few echinus spines and 

 foraminifera. 



Foraminif era : 

 Truncatulina, sp. 

 Amphistegina lessonii, d'Orb. 



No. 134. Top of upper cliff, southern end of east coast. 

 Limestones with few organisms ; Zithofhamnion, f oraminifera> 

 and echinus spines. In places this rock appears to be sheared. 



Foraminifera : 

 Amphistegina lessonii, d'Orb. 

 Polytrema miniaceum (Pallas). 



1 Abhandl. m.-ph. CL k.-bayer. Ak. Wiss., vol. x, 1868 (1870), p. 700, 

 pi. iii, figs. 17, 18, 35-7. 



