NOTES ON RETICULARIAN EHIZOPODA, 43 



-rV inch (2*5 millim.) in entire length ; it has two segments, 

 and appears to have had a third. Either of the other species 

 attains many times this size. The walls are thin, compact, 

 and brittle, and, as stated in the description, are largely made 

 up of sponge spicules. 



The " Challenger" dredgings have yielded specimens from 

 the South Pacific (2760 fathoms) and from the North 

 Atlantic (West Indies, 290 fathoms) ; Mr. Norman's were 

 from the material obtained on the cruise of the "^ Valor- 

 ous" (off Greenland, 1350 fathoms); and others have been 

 found at one at least of the " Porcupine" stations in the 

 North Atlantic (1215 fathoms). 



ASTRORIZA CORNUTA, U. Sp. PI. IV, figS. 14, 15. 



Characters. — Test free, irregular ; outspread or rounded, 

 with branching or tapering radiating processes ; interior fol- 

 lowing the same general form as the test; non-septate. 

 Branches either terminating in simple apertures, or furnished 

 with simple or bifurcating, open, chitinous tubes, which serve 

 the same end. Exterior very rough, composed of coarse 

 sand-grains firmly cemented together. Size, ranging from 

 ■2V inch (1*25 millim.) in the rounded forms, to 4- inch (5 

 millim.) in the outspread varieties. 



Accepting the view that the organism last described really 

 belongs to the genus Astrorhiza, there can be little doubt 

 that the specimens represented in PL IV, figs. 14, 15, also 

 pertain to the same group ; indeed, they exhibit something 

 like the mean of the characters ot A. arenaria and A. 

 catenata. Many of the specimens have very much the con- 

 tour of the former species, and differ from it principally in 

 shell texture, whilst some of the rounded forms are chiefly 

 distinguishable from A. catenata by possessing only a single 

 chamber when fully grown. As may be inferred from what 

 has been already said, the thick, loosely-aggregated test 

 appears to me to furnish the most significant character of 

 Astrorhiza limicola and A. arenaria, and therefore the 

 affinity of the species now described is with A. catenata 

 rather than with these. 



Specimens of Astrorhiza cornuta have been found at two 

 of the " Challenger" stations, namely, in the South Atlantic, 

 off Pernambuco, 350 fathoms, and in the South Pacific, off" 

 New Zealand, 1100 fathoms ; examples also occur at one of 

 the "Porcupine" stations in the North Atlantic, in 816 

 fathoms. 



