272 REPORT OF NATIONAL MUSEUM, 1897. 



sometimes mixed with sponge spicules, firmly united by a brown cement 

 substance; arms tubular, terminating in simple rounded apertures. 

 Localities. North Atlantic, and the Caribbean Sea (stations 2115, 

 2150, 2234, l>571) ? 380 to 1,350 fathoms. 



Genus RHIZAMMINA. 



Unattached masses of fine, flexible, simple or branching chitino- 

 arenaceous tubes. 



RHIZAMMINA INDIVISA Brady. 

 (Plate 15, tig. 2.) 



Slender, flexible, simple, chitinous tubes of a brownish color, thickly 

 incrusted with small foraminifera (mostly Globigerina) and very fine 

 sand. Test more or less contorted in drying; generally tapering toward 

 the extremities; apertures terminal, simple. Length, 3 to mm. (^ to J 

 inch). 



Localities. Southward of Long Island, the Straits of Yucatan, the 

 Gulf of Mexico, and the coast of Brazil (stations 2234, 2355, 2380, 2760), 

 400 to 1,400 fathoms. 



RHIZAMMINA ALG^EFORMIS Brady. 

 (Plate 15, fig. 1.) 



Slender, chitinous tubes, iucrusted with fine sand or small forami- 

 nifera; dichotoinously branched; quite flexible while wet, very brittle 

 when dry; found in tangled masses, from which it is extremely difficult 

 to separate an unbroken specimen. Length, indefinite; may be an inch 

 or more; diameter of tube, 0.12 to 0.3 mm. (._ >( \ () to -^ inch). 



Locality. - ff the west coast of Mexico (station 3415), 1879 fathoms. 



Family III. LITUOLlDJ:. 



Test arenaceous, usually regular in contour and more or less definitely 

 segmented; chambers frequently labyriuthic. 



Test composed of coarse sand grains, rough externally; often laby- 

 riuthic. 



Genus REOPHAX. 



Test free; composed of a single flask-shaped chamber, or of several 

 united in a straight, curved, or irregular line; never spiral. 



REOPHAX DIFFLUGIFORMIS Brady. 

 (Plate 16, fig. 2.) 



Test free, small, oval, pyriform, or flask-shaped; walls thin, inclosing 

 a single undivided chamber, and composed of rather coarse sand firmly 



