199 



outside by numerous longitudinal ribs; chambers formed by transverse septa, 

 perforated by a central or marginal tube. 



O. raphanus, O. raphanistrum, O. acicula, O. legumen. 



' fascia, ' obliqua, 



Nodosaria. Shell elongated, straight or slightly curved, subconical, 

 nodular; nodules globular, very smooth. Chambers formed by transvers 

 septa, perforated in the centre or near the margin. 



N. radicula, N. dentalina, N. siphunculus. 



Hippurites. Shell cylindrical, conical, straight or rather curved, multi- 

 locular, septa transverse. An internal, lateral channel, formed by two longi- 

 tudinal, parallel, obtuse and converging ledges; the last chamber furnished with 

 an operculum. 



A fossil. 



Conilites. Shell conical, straight, slightly bent; sheath thin, distinct 

 from the nucleus, which it contains. Nucleus subseparable, multilocular, 

 transversely divided by septa. 



A fossil. 



LITUOLATA.— Three Genera. 

 Shell partly spiral, the last whorl continuing in a straight line. 



Spirula. Shell cylindrical, thin, nearly transparent, multilocular, partly 

 turned into a discoidal spiral form; the whorls distant from each other, the 

 last produced in a straight line; septa transverse, equally distant, externally 

 concave; syphon lateral, interrupted; aperture orbicular. 



S. Peronii. 



Spirolina. Shell multilocular, partly discoidal spiral, the whorls contigu- 

 ous, the last terminating in a straight line; septa transverse, terminated by a tube. 

 A fossil species. 



Lituolites. Shell multilocular, partly turned into a discoidal spiral form; 

 the whorls contiguous, the last terminating in a straight line; chambers irreg- 

 ular; septa transverse and simple, without a syphon, the last perforated with 

 from three to six holes. 



A fossil species. 



