288 Messrs. W. K. Parker and T. Rupert Jones 07i some 



growth of calcareous matter from the free edges of the umbilical 

 portion of each chamber, which do not here quite touch each 

 other at their contact with the older whorls ; therein differing 

 from the habit of other Nonionina. Occasionally this overgrowth 

 extends further ap between the chambers [N. stellifera and N. 

 limba, D'Orb.), especially in the larger individuals, nearly filling 

 the sunken sutures throughout ; and the central mass is often 

 roughened and granular. 



In some specimens obtained at Pegwell Bay and Eastbourne, 

 this exogenous growth is traceable from a simple fringe on the 

 free edges above mentioned, to an overlapping, penthouse-like, 

 narrow plate, similar to what is seen on one surface in some 

 asterigerine Rosalince. 



This form is not common in the Norway dredgings. It ap- 

 proaches N, crassula in its general shape, but the umbilical slits 

 between the chambers and the accompanying astral overgrowth 

 give it characteristic peculiarities. These Nonionina, having 

 their chambers thus partially disconnected, form a link with 

 others, having minute pittings along the septa, towards consti- 

 tuting passage- forms into Polystomella^. 



The asterigerine Nonionina occur in the Mediterranean and 

 the Atlantic (Canaries), and are fossil at Grignon, Bordeaux, and 

 elsewhere. 



12. Nonionina striato-punctatay Ficht. & Moll, sp. 



Nautilus striatopunctatus, F. & M. Test. Microsc. p. 61. pi. 9. fig. a-c. 

 Nonionina striatopunctata, D'Orb. Ann. des Sc. Nat. vii. p. 294. no. 21. 



This interesting form with a pitted condition of the septa 

 (referred to above) occurs in the Red Sea (Fichtel and Moll), 

 and is common in the West Indies. We have found it also in 

 the Norway dredgings, but it was inadvertently omitted in the 

 drawings. 



13. Polystomella crispa, Linn. sp. PI. XI. fig. 19. 



Nautilus crispus, Linn. Syst. Nat. 12 ed. p. 1162. 



Polystomella crispa, D'Orb. Ann. des Sc. Nat. vii. p. 283. no. 1; Williamson, 



Trans. Microsc. Soc. vol. ii. p. 159. pi. 28; Schultze, Organ. Polyth. 



p. 62. pi. 4, &c. 



This well-known shell is not common in the Norway dredgings. 

 It is here represented by a small obtusely- edged and somewhat 

 gibbous form, which has not, however, much thickening at the 

 umbilicus of either surface. 



The P. crispa is a very protean Rhizopod, yielding numerous 

 varieties named by authors. Sometimes it is thick, and bears 



* Polystomella is also frequently Nonionine in the character of its 

 aperture. 



