162 



THREE CRUISES OF THE " BLAKE. 



species of Pelosina, a flask - shaped rbizopod with thick walls 

 composed of globigerina ooze. Another type of the same group 

 resembles a long-necked flask with branching calcareous pro- 

 jections, but thickly covered outside with fragments of sponge 

 spicules. Large fragments of a mammillary mass of loosely 



Fig. 490. — Sorosphsera confusa. 1 j°. (Brady.) 



crumbling character, Sorosjjhcera confusa (Fig. 490), are not 

 uncommon from the Caribbean globigerina ooze. 



Hyperammhia elongata (Figs. 491, 491 a), almost a cosmo- 



^to^^^fe- 



Fig. 491. 



Hyperammina elongata 



politan species, builds a long, slender tube which attains a length 

 of 15 mm. Sometimes it is constructed of siliceous sand and 



sponge spicules. It has been dredged 

 in the North Atlantic to nearly 1,800 

 fathoms. The genus dates back to the 

 silurian. Rhabdarnmina abyssorum 

 (Fig. 492), composed entirely of sili- 

 ceous sand-grains, is one of the most 

 characteristic forms of the deeper-water 

 sorum. f. (Brady.) rhizopods of the Caribbean, Gulf of 



