ON SOME FOSSILS FROM THE ISLANDS OF FORMOSA & RIU-KIU. 11 



width by 1 mm. in thickness ; inside dimensions of the two central 

 chambers taken together about .21mm. in width by .14 mm. in 

 depth ; chambers of the median plane very minute ; long axis of 

 lozenge about .02 mm. 



Form B. — Similar to the Form A in all respects save that 

 the initial chamber is too small to be measured. 



Occurrence : Very common in the limestone from Sonai, 

 Iriomoté Island, Yayeyama Group. The Form A in our slides 

 is more common than the Form B. 



Orbitoides (Lepidocyclina) sumatrensis, Brady. 

 (PI. I, fig. 7.) 



0. sumatrensis, Brady : Geol. Mag., 1875, p. 536, PI. XIV, 

 fig. 3 ; and Jaarh, Mijn. Ned. Ooste-Indië, 1878, Vol. 

 VII, Pt. II, PL II, fig. 3. 



0. {Lepidocyclina) sumatrensis, Newton and Holland : Ann. 

 Mag. Nat. Hist., 1899. Ser. VII, Vol. Ill, p. 259, PI. 

 X, figs. 7-12. 



0. {Lepidocyclina) Sumatrensis, Jones and Chapman : Mono- 

 graph of Christmas Island, 1900, p. 244, PL XX, fig. 6. 



To this species we refer the form shown in fig. 7 on Plate 

 I. It differs from the Sumatran and Bornean specimens only in 

 its smaller dimensions which are 1.5 mm. by .85 mm. 



Occurrence : Met with rarely in the Iriomoté limestone. 

 The Sumatran specimens were collected by Dr. Verbeek from 

 the marl-rock of Nias Island, off the West coast of Sumatra. 



