314 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



Genus STEPHANOSELLA Canu and Bassler, 1917 



STEPHANOSELLA INDISTINCTA, new species 



Plate 35, figs. 7, 8 



Description. — The zoarium is bilamellar and formed of lamellae 

 back to back; the fronds are small, undulated. The zooecia are 

 indistinct very little elongated, rectangular; the frontal is convex, 

 smooth, perforated by some scattered, irregular pores. Two sessile 

 avicularia are placed on each side of the apertura; a frontal, trans- 

 verse avicularium with pivot appearing frequently below the apertura. 

 The apertura is formed of a semilunar anter and of a wide triangular 

 rimule. The ovicell is large, buried in the distal zooecium, not 

 closed by the operculum; the area is subcircular, striated fanshaped. 



Measurements. — 



. f/m = 0.15 mm. „ . \Lz = 0.60 mm. 



Apertura, _ 1 c Zooecia 7 



^ [la = 0.15 mm. [Iz = 0.40-0.50 mm. 



Affinities. — This species differs from StepJianosella biaperta Michelin, 

 1845, in its larger tremopores and in the presence of the frontal avic- 

 ularium. Our specimens were dead. 



B C 



Fig. 131. — Opercula of Schizoporellae. 



A. Stylopoma distorta, new species. B. Stylopoma parviporosa, new species. 

 C, D. Lacerna signata Waters, 1889. 



Occurrence.— D. 4807. Cape Tsiuka, Sea of Japan; 41° 36' 12" N.J 

 140° 36' E. (common). 



Cotypes.— Cut. No. 8070, U.S.N.M. 



Genus STYLOPOMA Levinsen, 1909 



STYLOPOMA DISTORTA, new species 



Plate 36, figs. 1, 2 



Description. — The zoarium is multilamellar and encrusts pebbles. 

 The zooecia are distinct, separated by a deep furrow, somewhat 

 elongated, irregularly hexagonal, deformed; the frontal is convex, 

 covered with closely arranged tremopores, bearing frequently a small 

 oral avicularium or a small lateral one. The apertura is very little 

 elongated and is formed of a semicircular anter and of a narrow and 

 rounded rimule. The ovicell is porous and entirely covers the aper- 

 tura. The spathulate interzooecial avicularium is very rare. 



Measurements. - 



k = 0.16mm. „ . \Lz = 0.55 mm. 



lz = 0A5 mm. 



A \ha = 0.16 mm. „ 



Apertura 7 _ ., _ Zooecia 



r Ua = 0.15 mm. < 



