
No. 464.] STAGES IN LAGENIDE 551 
among the Cephalopoda or to Vermetus or Magilus among the 
Gastropoda.  . 
Spinose or ** Wild” Growths.— In Polymorphina and Sagrina 
of this family the last chambers are often peculiarly different 
from the preceding ones. In Polymorphina orbignyit, as figured 
by Brady, Parker, and Jones (Trans. Linn. Soc. London, vol. 
27, p. 244, pl. 42, fig. 38c) the last chamber is marked by a 
eculiar fistulose growth, greatly differing from the preceding 
regular chambers of the species (Fig. 23). Such growths are 

L ig mn with peculia fi 1 g +h in senescence 
Pata d'Orb. with “wild ” growth. (After Brady.) 


Fic. 23.— Poly ‘p 
n c. 
FIG. 24 

not infrequent in various other genera. Corresponding “ wild” 
growths appear in certain species of Cristellaria. In Umgerina 
aculeata d’Orb. (Fig. 24) similar characters appear. This spe- 
cies in its younger development has simple longitudinal costae. 
Later, however, there is a thickening by addition from the out- 
side and the last chamber is covered with a decidedly spinose 
development totally different from the previous ornamentation. 
This spinosity may continue, extending progressively posteriorly 
until it envelops the whole shell, covers the preceding cham- 
bers, and hides all traces of the typical earlier ornamentation. 
These growths seem to be best regarded as senescent charac- 
