242 Christmas Island. 



Following closely upon No. 845 is No. 844, Trhicli we next 

 proceed to examine. 



This is a white limestone with numerous large Orhitoides 

 apparent on both weathered and fractured surfaces. It is finely 

 crj'stallized, and the rock has been fi'actured here and there with 

 the rifts now infilled with clear secondary calcite. 



The organic contents of the rock are LiOiothamnion, many 

 foraminifera, amongst which the Orhitoides mentioned are con- 

 spicuous, and numerous polyzoa. 



The foraminifera are as follows : — 



Spirolocidina excavata, d'Orbigny. 



SpirolocxUna excavata, d'Orbigny, 1846, Foram. Foss. Vienne, p. 271, pi. ivi, 

 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 jVo. 844. 



Miliolina alveoliniformis, Bi'ady. 

 One individual in transverse section appears in this slide. 



Sigmoilina, sp. near S. celata (Costa). 



Spirolocidina 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. 

 Sigimilina 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 jS^icobar Islands. 



Textularia nigosa (Eeuss). 

 Yeiy rare in rock-specimen ISo. 844. 



AmpMstegina lessonii, d'Orbigny. 

 The specimens in jS'o. 844 are both common and characteristic. 



Orhitoides {Lepidocyclina) insulce-iiatalis, sp. nov. (PI. XX, Fig. 5.) 



Near "Lepidocyclina, spp. c and c','' Verbeek & Fennema, 1896, Descr. geol. 

 Java et Madoura, vol. i, pi. 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 



