368 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 14 



The original description of Stephanosella, as given above, needs only 

 a few comments. The frontal is smooth in the young but becomes ir- 

 regularly roughened with age; the ovicell at first is prominent but 

 becomes covered by the excessively thick frontal wall except for a small 

 sculptured area on the top ; the aperture of the ovicelled zooecia differs 

 very little in size from the others. 



The genus Buffonellaria Canu and Bassler, 1927, presents no funda- 

 mental differences and is a pure synonym ; the genotype, Hippothoa 

 divergens Smitt, is merely a thinner-walled and smoother Stephanosella. 

 Dr. Bassler (in litt.) agrees to this synonymy. 



Stephanosella biaperta (Michelin), 1845 

 Plate 42, figs. 1-2 



Eschara biaperta Michelin, 1845:330. 



Lepralia biaperta. Busk, 1859:47. 



Escharella linearis forma biaperta, Smitt, 1867:14. 



Schizoporella biaperta, Nordgaard, 1906:15. 



Not Hippothoa biaperta, Smitt, 1873:46. 



Schizoporella biaperta, Hincks, 1880:255 (in part). 



Not Schizoporella biaperta, Osburn, 1912:237. 



Not Stephanellosa (sic) biaperta, Canu and Bassler, 1925:30. 



Schizoporella biaperta, Robertson, 1908:287 (in part). 



Not Stephanosella biaperta, Canu and Bassler, 1923:99. 



Zoarium encrusting, sometimes multilaminate and forming rough 

 colonies. Zooecia moderate in size, 0.55 to 0.70 mm long by 0.35 to 0.50 

 mm wide, ovate to roughly hexagonal in form, slightly inflated and 

 distinct when young. The frontal is an olocyst, smooth and veined in 

 the young but becoming very thick and somewhat roughened ; a row of 

 4 or 5 areolar pores on each side, difficult to see except when calcined. 

 Aperture a little broader than long, about 0.12 mm long by 0.15 wide, 

 the proximal border with a shallow rounded sinus. The operculum has 

 the form of the aperture, well chitinized, yellowish in color, the border 

 with a narrow sclerite, a small lucida at the points of attachment and 

 the muscle attachments well within from the border (in typical schizo- 

 porellid fashion). The peristome is low and thin, without spines. The 

 avicularia are of two kinds, ( 1 ) lateral-oral, usually paired on a small 

 elevated chamber at the sides of the aperture, the mandible either 

 rounded or pointed; (2) a larger frontal avicularium, considerably 

 elevated with a pointed mandible, the chamber connected with one of 

 the areolar pores. 



