CHARACTERISTIC DEEP-SEA TYPES. — RHIZOPODS. 169 
walls, the greatest variety of. forms and of deviation from the 
parent type results. 
Pulvinulina auricula (Figs. 515, 515 a) is a handsome hya- 
Fig. 515. Fig. 515 a. Fig. 516. Fig. 517. 
Pulvinulina auricula. 4,5.  (Goés.) Pulvinulina Menardii. 12. (Goés.) 
line species, and its ally, P. Menardii (Figs. 516, 517), is one 
of the most common deep-water species. It is also pelagic. 
Another deep-water form is Truncatulina Un- 
geriana. (Fig. 518.) The little Polytrema 
miniaceum (Fig. 519) is a delicate red parasitic 
foraminifer, occurring 
everywhere in the 
Fig. 518. — Trun- West Indies, which 
catalina Unger- yegembles certain mi- 
ana. 15, (Goös.) 
nute eorals. It has a 
long geological history, dating back 
to the devonian. Of the Nummuli- 
nidee, Polystomella crispa is one of 
the most abundant West Indian types 
Fig. 519. — Polytrema minia- 
of moderate depths. ceum, 1? 
