84 PKOCEEDINGS OF THE NATIOITAL MUSEUM vol. 72 



Range. — Eocene (Jacksonian) — Recent. 



The known species are as follows : 



Stenopsis (Porina) fenestrata Smitt, 1873, Gulf of Mexico. 



Stenopsis unirostris Canu and Bassler ms., Sulu Sea. 



Stenopsis cylindrica, new name ( = Gigantopora fenestrata Waters 

 1908), Red Sea. 



Stenopsis (Galeopsis) longicollis Canu and Bassler, 1920, Jacksonian. 



Stenopsis (Galeopsis) cy clops Canu and Bassler, 1920, Jacksonian. 



Stenopsis (Porina) tuberculosa Maplestone, 1902, Miocene. 



This is an equatorial genus. The ovicell opens into the peristomie. 



Affinities. — Stenopsis differs from Galeopsis JuUien, 1903, in the 

 absence of cardelles and in its opercula without bands or points. It 

 differs from Gigantopora Ridley, 1881, which it resembles in general 

 aspect, in the presence of a granular tremocyst. It differs from 

 Gephyropliora Busk, 1884, in its longer peristomie and in the absence 

 of rimule and points to the operculum. 



STENOPSIS FENESTRATA Smitt, 1873 



Plate 14, Figures 9, 10; text Figure lid 



1873. Hippothoa fenestrata Smitt, Floridan Bryozoa. Kongl. Svenska Vet- 

 enskaps-Akademiens, Handlingar, vol. 11, p. 47, pi. 6, fig. 112. 

 (Not Gigantopora fenestrata Waters, 1908.) 



Tir J * i [y^a = 0.10 mm. 



Measurements. — Apertureu _ .^ 



^ iZa = 0.12 mm. 



„ . [/t = 0.10 mm. 



Spiramen-i, _ ,^ 

 ^ lt = 0.12 mm. 



ry . Ji2 = 0.90-1 .00 mm. 



^"^^^^1^ = 0.35-0.40 mm. 



Structure. — The aperture is semielliptical; its exact form is aptly 

 defined as "rounded-quadrangular" by Smitt; it is visible at the bot- 

 tom of the peristomie, which must be broken in order to render it 

 clearly visible. The operculum has the same form and its proximal 

 border is slightly concave; it bears neither muscular attachments nor 

 ornaments; it is thin and fragile. 



The peristome is thin, orbicular, very long, not covered by the 

 tremocyst. It bears laterally a single triangular, thin avicularium, 

 with the beak above. 



The spiramen is placed at the base of the peristomie ; it is salient 

 and in the form of a lunar crescent with a distal concavity; its dimen- 

 sions are exactly those of the aperture. The ovicell is globular and 

 opens into the peristomie. 



Affinities. — Waters, 1908, determined under this name a different 

 species from the Red Sea and for which we have proposed the name 

 of S. cylindrica because of its zooecial aspect. Stenopsis fenestrata 

 differs from it in its long peristomie, in the great distance between 



