BY FREDERICK CHAPMAN. 755 



All the specimens, so far as seen, commence with a small initial 

 chamber {i.e., they are microspheric). Length of a typical speci- 

 men '2 mm.; thickness at centre 0-72 mm. Another example 

 measures 1 mm. in diameter. 



Occurrence. — Very abundant in limestone from Bartaleppe, 

 Malekula(No.l08). 



Observations. — -There is little or no doubt that Verbeek's 

 Alveolina, which he found in the Lower Miocene limestone in the 

 PalabouhcUi District of Java, is the same as our species from 

 Malekula which I now name A. cucumoides. Verbeek ffives as 

 the dimensions of the Javan examples, length 3*50 mm., thickness 

 75 mm., and the number of spiral turns as 6 to 7. He also 

 states that the central chamber was not clearly seen in his 

 preparations. 



The above species differs markedly from Alveolina elongata 

 d^Orhigny ( = 4- Jricmenti/ormis Schwager),* a species from the 

 Middle and Upper Eocene, in its irregular contour, since it is 

 not evenly cylindrico-fusiform as in Schwager's species, but is con- 

 stricted on either side of the median axis; otherwise the shape 

 and disposition of the chambers, and the structure of the test 

 are very similar. It is especially interesting to meet with 

 Alveolina in its microspheric stage, since all recorded recent 

 forms have hitherto only been represented b}^ the megalospheric 

 type of shell. Schlumberger gives a single instance,! discovered 

 by Munier-Chalmas, in which the microspheric form occurred in 

 a fossil species. With regard to a recent species of the genus, 

 Alveolina hoscii Defr., I have lately met with some examples 

 which also show this unusual condition. They are from the 

 'Great Barrier Reef of Queensland, in material obtained throuo-h 

 the courtesy of Messrs. C. Hedley and J. Gabriel. The specimens 

 are, however, very rare compared with the associated megalo- 

 spheric form. 



* Palceontographica, Vol. xxx. 1883, p. 100, pl.xxv., figs.4a- 

 t Assoc. Franc. Avan. Sci., Congr^s de Rouen, 1883, p. 526. 



