NOTES ON RETICULARIAN RHIZOPODA. 39 



with its much smaller size — often not -yV in. in entire length 

 — and its occurrence in localities in which the other is not 

 found at all, there can be little doubt of its title to a distinc- 

 tive appellation. 



The best " Challenger " specimens of Rhahdammina 

 linearis have been obtained from dredgings off Sombrero 

 Island and off Culebra Island (West Indies) in 450 fathoms 

 and 390 fathoms respectively, and from a deeper sounding 

 (1900 fathoms) off the coast of South America, in latitude 

 35° 59' S. 



G^ewws— RHIZAMMINA, nov. 



(jot^a, a root ; afxfiog, sand). 



Rhizammina algjeformis, n. sp. PI. IV, figs. 16, 17. 



Characters. — Test free, tubular, branching, flexible ; form- 

 ing tangled weed-like tufts of indefinite size. Texture 

 chitino- arenaceous, slightly rough externally ; colour brown. 



Amongst the doubtful organisms which have from time to 

 time been dredged in deep-water in various parts of the 

 world, minute, branching, flexible tubes, with rough exterior 

 from embedded sand-grains, have not been the least frequent. 

 These have hitherto occurred in comparatively small 

 numbers, and though they have been supposed to belong to 

 the Rhizopoda, their precise nature has not, as far as I am 

 aware, been investigated. At one of the " Challenger " 

 stations off the western coast of South America, in about 

 the latitude of Valparaiso, the principal part of the con- 

 tents of the dredge consisted of a weed-like organism of this 

 sort. 



At first sight its tangled threads bear considerable resem- 

 blance to masses of some Melanospermous Alga, such as 

 Stilophora rhizodes, but quite apart from the fact that the 

 sarcode animal was observed whilst still in fresh condition, 

 the structure of the investment of the preserved specimens 

 is sufficient to determine its Rhizopod affinities. My friend 

 Mr. Hollick has not been quite so successful as is his 

 wont, in the figure representing a bit of the organism of the 

 natural size (PI. IV, fig. 16), but the enlarged drawing 

 (fig. 17) gives very accurately the appearance of a portion of 

 one of the younger and more transparent branches mounted 

 in Canada balsam. 



When spread out on a white surface the mass is seen to 

 be composed of branching tubes, varying in diau.eter from 

 s-ro to -^ of an inch (0'53 to 0-32 millim.). What their 



