162 



THREE CRUISES OF THE " BLAKE. 



species of Pelosina, a flask -shaped rhizopod 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 conf usa. Y (Brady. ) 



crumbling character, Sorosphcera conf usa (Fig. 490), are not 

 uncommon from the Caribbean globigerina ooze. 



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



Fig. 491. Fig. 491 a. 



Hyperammina elongata. \. (Goes.) 



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. Rhdbdammina dbyssorum 

 (Fig. 492), composed entirely of sili- 

 ceous sand-grains, is one of the most 



K g . 492. -Rhabdanunina abys- characteristic forms of the deeper-water 

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



