FOEAMINIFERA OE THE KEEIMBA AECHIPELAGO. 375 



Family Lituolid^. 

 NouRiA, gen. n. 



During the examination of the Kerimba material, we found at Stations I., III., and IX. 

 a considerable number of specimens of a Rhizopod which, on a superficial examination, 

 appeared to be assignable to the species Reophax ampuUacea Bradj^ They attracted 

 closer attention, however, by the fact that many of them were highly conspicuous 

 objects, owing to the incorporation of relatively large and highly coloured mineral 

 particles in their tests, as well as by their large size and irregular contour. These 

 minerals stand out strikingly, by reason of their shapes and colours, from among the 

 quartz-grains and calcareous particles of which the shell is mainly constructed. 



A more careful examination of the specimens, including some mounted in balsam 

 and others laid open for the purpose, disclosed the interesting fact that the shell, 

 instead of being monothalamous, as in Seophax ampuUacea, was polythalamous and 

 that the chambers were arranged more or less spirally in a polymorphine manner. 



Isomorphism with hyaline genera is a well-recognised feature in the Lituolinas,' 

 Seophax being isomorphous with Lagena and Nodosaria and Haplopliragmium with 

 many hyaline genera (e. g., Cristellaria, Botalia, Nonionina, Glohigerina, etc.), but no 

 case of isomorphism with the hyaline genus PoIymor]}hina has yet been recorded*. 

 Among the Kerimba specimens of Nouria polymorphinoides there is considerable 

 variety of forms, comparable mainly with Polymorphina compressa d'Orbigny, but also 

 with P. ohlonga Williamson. 



This discovery led us to re-examine some specimens in our cabinet from deeper water 

 off the coast of New Zealand, which we had also referred with some hesitation to 

 Peophax awpxillacea. They prove, on a more critical examination, to be structurally 

 identical with the Kerimba specimens, and are unquestionably constructed by a 

 similar organism. The New Zealand specimens, which were found in material sent to 

 us by Mr. R.. L. Mestayer, F.R.M.S., of Wellington (N.Z.), were dredged by Captain 

 Bollons off the Poor Knights' Islands (35° 5' S., 174° 7' W., depth 60 fms.). They 

 differ considerably from the Kerimba specimens in external appearance, being much 

 more neatly constructed, owing to the fact that the test is almost entirely built up of 

 transparent flakes of a volcanic mineral, with a few incorporated sponge- spicules, 

 giving a much more regularly compressed and finished appearance to the test than 

 is observable in the somewhat coarsely constructed Kerimba shells (PI. XXXVII. 

 figs. 13-15). The New Zealand specimens are, as a rule, isomorphous with 

 Polymorphina compiressa d'Orbigny, but occasionally with P. oblonga Williamson. 



* The species Polymorphina silicea Schultze (' Organismus der Polytbalamien ' (Leipzig, 1854), p. 61, pi. vi. 

 figs. 10, 11) is really Verneuilina polystrojAa (Reuss), and is adopted as a synonym of that species (cf, Bradj-, 

 ' Challenger ' Eeport, 1S84, p. 386). 



