548 Transactions of the Society. 



members of the group of Puhinulina elegans for which has been 

 instituted the genus Epistomina; whilst something resembling the 

 second may be found in the cell- walls of Lagena Herhcigiana and 

 Nodosaria inter cellular is. 



Taken in the abstract these form a very natural group, and it 

 becomes a question whether it is more convenient or even more 

 zoologically accurate to treat them as a distinct genus, or to scatter 

 them amongst already existing genera. It must be noted that they 

 are not represented merely by a few obscure examples whose peculi- 

 arities might be ascribed to local influences, but all the forms here 

 described are found in the greatest profusion all over the Malay 

 Eegion. It is one of the problems of zoology that species so well 

 marked and existing in such astonishing abundance should not 

 hitherto have been observed in our existing oceans, nor in any of 

 the geological formations. 



Mimosina affinis sp. n., plate IV. fig. 11. 



Test ovate ; chambers globular, arranged tri-serially and rapidly 

 increasing in size ; sutures depressed. Sutural orifice a slit, usually 

 cribrate ; superior orifice a curved depression with the extremities 

 rounded. Length ■ 35 mm. 



This is an isomorph of Bulimina affinis d'Orbigny, having little 

 to distinguish it beyond the compound aperture and the structure of 

 the shell-wall. The specimens are remarkably uniform in appearance, 

 where there is any tendency to variation it is in the direction of 

 Mimosina spinulosa. 



It is the most abundant species of the genus, occurring in great 

 profusion at nearly all the Stations in both Areas. 



Mimosina spinulosa sp. n., plate IV. fig. 12. 



Test elongate, trifacial, tapering towards the aboral end, margins 

 acute ; chambers slightly inflated, the marginal angle acute and 

 slightly overlapping the preceding chambers, arranged tri-serially ; 

 sutures more or less depressed. Sutural orifice a narrow slit ; 

 superior orifice large and triangular or semilunar. Length 0*50 

 mm. 



This is an isomorph of Verneuilina. It is very variable not only 

 in length, but in the form and extent of inflation of the chambers, as 

 well as in the degree of acuteness of the peripheral margins. 



It is abundant, but less so than the other forms. 



Mimosina spinulosa var., plate IV. fig. 13. 



In this variety the marginal angles of the chambers are developed 

 into lobes terminating in a spine. The chambers are more inflated 

 and less regularly arranged, and the test is often contorted. 



