538 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 54. 



radiates protruding through it. Total length of body 28 mm., great- 

 est breadth about 10 mm., wall about 1 mm. thick, osculum about 

 5 mm. in major diameter. The color in alcohol is whitish. The tex- 

 ture is fairly firm and elastic. 



Structure. — The dermal cortex is fairly thick. It is about 0.4 mm. 

 thick. The gastral cortex is also well developed, but is distinctly 

 thinner than the dermal, measuring about 0.25 mm. in thickness. 

 The canal system is of the syconoid type. The flagellate chambers 

 are rather short, cylindrical, straight, not unfrequently slightly 

 branched; each passes at the apopyle into a long exhalant canal, a 

 diaphragm occurring at the boundary. The dermal skeleton con- 

 sists of few laj^ers of triradiates, which are tangentially but other- 

 wise rather irregularly disposed. Large oxea, grouped into small 

 bundles and placed perpendicularly or somewhat obliquely to the 

 dermal surface, project far beyond the surface, their proximal parts 

 being deeply imbedded in the chamber layer. The tubar skeleton is 

 made up of triradiates in two or three irregular layers, as well as of 

 the basal rays of subgastral triradiates and quadriradiates. The gas- 

 tral skeleton forms a thin layer, consisting mainly of gastral quadri- 

 radiates, of which the basal ray generally points toward the base and 

 apical ray projects into the gastral cavity in oblique inclination to- 

 ward the osculum. In addition to the quadriradiates there occur in 

 the layer the paired rays of subgastral triradiates as well as the facial 

 rays of subgastral quadriradiates. The skeleton of oscular margin 

 consists of interlacing oxea, triradiates, and quadriradiates. The 

 oxea are arranged longitudinally ; the basal rays of tri- and quadri- 

 radiates are directed regularly downward. 



Spicules. — Dermal triradiates (a) slightly sagittal. All rays 

 slightly irregular in outline, nearly equally thick, lying in one plane. 

 Basal rays nearly straight, usually slightly shorter than paired rays, 

 90-260/A long and 20/x thick at base. Paired rays subequal, nearly 

 straight, excepting a slight curvature near base, 180-260/* long and 

 20/x thick at base. 



Tubar triradiates (h) sagittal. Eays slightly irregular in outline, 

 lying not in one plane. Basal ray much longer and slightly thicker 

 than paired rays, nearly straight, 290-370ijl long and 21— 28tJ- thick 

 at base. Paired rays slightly curved at base and nearly straight or 

 weakly crooked in the remaining parts, 160-220ti long and 20-24[ji. 

 thick at base. 



Subgastral triradiates (c) strongly sagittal. Eays sharply pointed, 

 nearly equally thick, lying not in one plane. Basal ray straight, much 

 longer than paired rays, 150-240[jl long and 12-16[jl thick at base. 

 Paired rays strongly diverging, curved rather angularly in the 

 middle parts, 130-170/x long and 16-20/* thick at base. 



