570 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxiv. 



Distribution.— ^ouih. coast of Molokai: Station 3838, 92-212 

 fathoms; Station 3853, 115-134 fathoms (Cat. No. 22563, U.S.N.M.) ; 

 Station 3859, 138-140 fathoms. 



Section HOLAXONIA. 



Colony with an axis consisting of amorphous horny or calcareous 

 material, or both, and not pierced by longitudinal canals, excepting 

 a central one. 



Family ISID^ Gray (modified by Wright and Studer). 



Axis cylinder composed of alternating horny and calcareous joints, 

 the latter not of fused spicules, but amorphous. 



Genus CERATOISIS Pereival Wright. 



Branches, when present, arising from the calcareous joints of the 

 axis cylinder. Polyps nonretractile, a circlet of diverging spicules 

 around the oral region. Spicules smooth. 



CERATOISIS FLABELLUM, new species. 



Plate XLIII, fig. 1 ; plate XLVII, fig. 3. 



All of the specimens were secured in a fragmentary condition. 

 The largest piece is about 275 mm. long; calcareous nodes 17 to 27 

 mm. long, horny nodes 1^ mm. long. The branches arise from the 

 calcareous joints, on opposite sides of the stem; irregularly disposed 

 but all in the same plane. Polyps on front and sides of stem and 

 branches, unequally distributed, often denser on one side than on the 

 other, standing at various angles with stem ; about 4 mm. high, 2 mm. 

 broad, cylindrical. The tentacles are folded loosely over the oral disk. 



Spicules very long needles, attaining a length in some instances of 

 5 mm. ; vertical in walls of calyces, on the distal portion of which 

 they project upward as sharp points between the tentacle bases. The 

 proximal part of calyx wall is overlaid with similar long needle- 

 shaped spicules, often more or less obliquely disposed. Similar spic- 

 ules are sparsely disposed in the cortex, where they are longitudinally 

 disposed, and sometimes branched at one end, the two or three 

 branches being parallel to the axis of the spicule. 



The main stem and larger branches appear to be somewhat flat- 

 tened. The polyps are distributed on all sides of smaller terminal 

 branches, but are usually thicker on the edges. 



Color. — Ivory white, the nodes purplish brown. 



Type.— Qui. No. 25390, U.S.N.M., Albatross Station, unknown, 

 Hawaiian Islands. 



