22 THE FORAMINIFEKA 



Since that time, however, this st)-ucture has been 

 detected in nearly all genera which have been made 

 the subject of careful observation. The following is 

 a list of such genera, with the authorities : Gromia 

 (Wallich, Max Schultze) ; Spiroloculina (Hertwdg) ; 

 Miliolina (Schulze) ; Peiieroplis (Biitschli) ; Orhitolites 

 (Blitschli, Lister) ; Dendroplinjd (Mobius) ; Saccmn- 

 mina (Khumbler) ; TextuJaria (Biitschli, Hertwig) ; 

 Lagena (M. Schultze, F. E. Schulze, Griiber, 

 Biitschli) ; Glohigeriua (Hertwig) ; Hpirillina 

 (Biitschli) ; Discorhiyia (Biitschli) : Truiicatuliiui 

 (Lister); Botalia (F. E. Schulze); Calcarina 

 (Biitschli) ; Polijstoinella (F. E. Schulze, Lister, 

 Verworn) ; Ampliistegina (Biitschli) ; Hefei'ostegijia 

 (Chapman) ; Cycloclypeus (Lister, Chapman). 



The nucleus of the Foraminifera varies in size 

 even in the same species. Lister's observations 

 regarding the nucleus of PoJustonieUa crispa show it 

 to vary in its diameter from '018 to "066 mm. The 

 nucleus often contains more or less numerous smaller 

 bodies (nucleoli). 



F. E. Schulze described the nucleus of Polystomella 

 striatopunctata, and stated that it was a round body 

 having, in some cases, a diameter of "056 mm. and 

 surrounded by a conspicuous membrane of consider- 

 able thickness; this latter appearance, however, seems 

 to be exceptional, and Lister remarks that there is 

 usually no perceptible investment of the nucleus 

 other than the reticulum. Highly refracting nucleoli, 

 lying in a clear and apparently Huid substance, occu- 

 pied the interior. In quite young specimens only one 



