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. 

 Pulvinulina auricula. 



Fig. 515 a. 

 ^>. (Goes.) 



Fig. 516. 

 Pulvinulina Menardii. 



Fig. 517. 

 . (Goes.) 



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- 

 (jeriana. (Fig. 518.) The little Polytrema 

 miniaceum (Fig. 519) is a delicate red parasitic 

 foraminifer, occurring 

 everywhere in the 

 West Indies, which 

 resembles certain mi- 

 nute corals. It has a 



long geological history, dating back 



to the devonian. Of the Nummuli- 



nidae, Polystomella crispa is one of 



the most abundant West Indian types Fig 519> _ Polytrema 



of moderate depths. ceum. \ a 



Fig. 518. Trun- 

 catulina Ungeri- 

 ana. if. (Goes.) 



