262 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



distally and laterally by a projecting margin; the zooecia frequently, occurring in 

 two forms a and B and provided with a large operculum armed with teeth, which 

 is suspended by strong hinge-teeth ; the polypide-tube is never continued proximally 

 beneath the cryptocyst cover. (After Levinsen, 1909.) 25 tentacles. 



Genotype. Steganoporella (Memoranipora) magnilabris Hincks, 1881. 



Range. Lutetian-Recent. 



The known fossil species of this genus are : 



Steganoporella (Gaudryanella] asymetrica Canu, 1907, Lutetian of the Paris 

 Basin. 



Steganoporella (Gargantua) firma Canu. 1007, not Reuss, Lutetian of the 

 Paris Basin. 



Steganoporella similis Koschincky, 1885, Lutetian of Bavaria. 



Steganoporella (Vincularia) haidingeri Reuss, 1869. Priabonian of the Vicentin. 



Steganoporella (Lepralia) firma Reuss, 1867. Priabonian of the Vicentin. 



Steganoporella (Escliara) elegans Milne-Edwards, 1838, Aquitanian-Helvetian 

 of France. 



Steganoporella elegans Smitt, 1873 (not Milne-Edwards, 1838), still lives off 

 the coast of Florida at a depth of 15-37 fathoms. 



STEGANOPORELLA JACKSON ICA, new species. 



Plate 39, figs. 9-16. 



Description. The zoarium is bilamellar formed of two layers back to back 

 and easily parted. The a zooecia are very elongated, narrow, distinct; the mural 

 rim is thin, salient; the cryptocyst is deep, granular, and porous; the opesium is 

 semilunar and transverse; there is no polypide-tube. but a small polypidian convexity 

 is present; the two opesiules are small, rounded, lateral incisions, quite indistinct; 

 the inner partition is very oblique. The B zooecia are twice as large, ogival, larger 

 at the top than at the bottom; their polypide-tube is salient and complete: the two 

 opesiules are two deep, rounded incisions; the opesium is bordered by a double 

 collar (oral arch); the distal niche is large, smooth, deep; the B zooecia always 

 engender two new rows of a zooecia. 



'Z2=0.46-0.50 mm. [ Ao=0.12 mm. 



measurements. a zooecia , 7 nri . Opesium , ,. . 



!fo=0.24mm. lZo=0.16-0.20mm. 



. (7,3=1.20 mm. 

 B zooecia \ 7 _ . 



us=0.50mm. 



Variations. It is rather remarkable that if the a zooecia become enlarged 

 the B zooecia are shorter. 



The frontal is a direct tremocyst (fig. 14) in which the granulations of the 

 cryptocyst often fill up the perforations. 



Only the B zooecia have a distinct polypide tube (figs. 10, 16). After wearing 

 away the frontal the a zooecia are seen to have an oblique partition more elevated 

 at the top than at the base (fig. 13). Similar abrasion on the dorsal side permits 



