242 Christmas Island. 



rollowing closely upon Ko. 845 is No. 844, wHcli we next 

 proceed to examine. 



This is a white limestone with numerous large Orhitoides 

 apparent on both weathered and fractured surfaces. It is finely 

 crystallized, and the rock has been fractured here and there with 

 the rifts now infilled with clear secondary calcite. 



The organic contents of the rock are Lithothamnion^ many 

 foraminifera, amongst which the Orhitoides mentioned are con- 

 spicuous, and numerous polyzoa. 



The foraminifera are as follows ; — 



Spiroloculina excavata^ d'Orbigny. 



Spiroloculina excavata, d'Orbigny, 1846, Foram. Foss. Vienne, p. 271, pi. xvi, 

 figs. 19-21; Brady, 1884, Eep. ChalL, vol. ix, p. 151, pi. ix, 

 figs. 5, 6. 



A very fine and perfect transverse section of the above form was 

 noticed in ]^o. 844. 



Miliolina alveoliniformis, Brady. 

 One individual in "transverse section appears in this slide. 



Sipno'ilina, sp. near ;S^. celata (Costa). 



Spiroloculina celata, Costa, 1855, Mem. Accad. Napoli, vol. ii, p. 126, pi. i, 



fig. 14; 1856, Atti dell' Accad. Pont., vol. vii, pi. xxvi, fig. 5. 

 Flanispirina celata (Costa), Brady, 1884, Eep. Chall., vol. ix, p. 197, pi. viii, 



figs. 1-4. 

 Sigmo'ilina celata (Costa), Schlumberger, 1887, Bull. Soc. Zool. France, vol. xii, 



p. Ill, pi. vii, figs. 12-14 ; Goes, 1896, Bull. Mus. Comp. Zool. 



Harvard Coll., vol. xxix, No. 1, pt. 20. 



There is not much doubt that our section (cut transversely) is 

 referable to the above species. Its earliest appearance as a fossil 

 has hitherto been in the Pliocene of the Mcobar Islands. 



Textularia rugosa (Eeuss). 

 Yery rare in rock-specimen 'Eo. 844. 



Amphistegina lessonii, d'Orbigny. 

 The specimens in jSTo. 844 are both common and characteristic. 



Orhitoides {Lepidocyclina) insuIce-nataliSf sp. nov. (PL XX, Fig. 5.) 



Near ^' Zepidocyclina, spp. c and c','' Verbeek & Fenneraa, 1896, Descr. geol. 

 Java et Madoura, vol. i, pL xi, figs. 166, 167 ; vol. ii, p. 1177. 



This species is very conspicuous from the later Miocene lime- 

 stones of Christmas Island. It is of large dimensions, being often 



