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, 2571), 380 to 1,350 fathoms. 



Genus RHIZAMMINA. 



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

 arenaeeous tubes. 



RHIZAMMINA INDIVISA Brady. 

 (Plate 15, fig. 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 6 mm. (^ to^ 

 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 ALGiEFORMIS Brady. 

 (Plate 15, fig. 1.) 



Slender, chitinous tubes, incrusted with tine sand or small forami- 

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

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

 toseparatean unbroken specimen. Length, indefinite; may be an inch 

 or more; diameter of tube, 0.12 to 0.3 mm. ( ¥ ^o to ~ - inch). 



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



Family 111. LITUOLID^E. 



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

 segmented; chambers frequently labyrinthic. 



Subfamily LITTJOI.IlSr^K. 



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

 rinthic. 



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 tirmly 



