52 HENRY B. BRADY. 



minute structure of the test is identical with that of some 

 varieties oi Reophax ; and in the absence of any distinguishing 

 character, save the completion of growth in a single chamber 

 instead of running on to form several segments, I am not dis- 

 posed to create a fresh genus for its reception. It may be 

 objected that the Lagence have been separated generically from 

 the Nodosaria on the ground of the monothalamous and poly- 

 thalamous conditions of their respective tests. Without 

 stopping to debate the propriety of this division from a 

 strictly zoological point of view, two pleas may be urged in 

 favour of it ; firstly, that amongst the Lagena there are many 

 varieties of surface ornamentation quite unknown in the 

 Nodosarian series, which is strong evidence against the 

 former being merely an arrested condition of the latter; and, 

 secondly, the convenience of generic subdivision where there 

 are so large a number of forms to be named and arranged. 

 Neither of these reasons are applicable to the present case. 



Amongst the hyaline Foraminifera only two globular 

 or subglobular monothalamous types are recognised — 

 Lagena and Orbulina ; but amongst the Arenacea the simple 

 spheroidal forms pertain to at least four or five genera, the 

 most important of which are Psammosphcera, Saccammina, 

 Hormosina, and Reophax. With the doubtful exception of 

 Psanimosphcera, all of these have polythalamous as well as 

 monothalamous species. 



The minute size of Reophax diffiugiformis , its flask-like 

 contour, and peculiar shell texture, are sufficient for its 

 identification. 



It appears to be essentially a deep-sea species, but of wide 

 geographical distribution. I have note of its occurrence at 

 five of the '' Challenger" stations, of which one is in the 

 North Atlantic, two are in the South Atlantic, and two in 

 the South Pacific. In one of these the depth is 1900 

 fathoms, the other four vary from 2200 to 2740 fathoms. 



Eeophax nodulosa, n. sp. PI. IV, figs. 7, 8. 



Characters. — Test long, slender, tapering, straight or 

 arcuate ; consisting of several (usually less than twelve) 

 segments, joined regularly end to end, and more or less em- 

 bracing. Segments oblong, rounded, somewhat inflated, 

 increasing in size from the first to the latest formed. Exte- 

 rior more or less rough ; interior neatly finished. Size 

 very variable — sometimes as much as an inch (25 millim.) 

 in length. 



