262 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
clistally 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 proximallv 
beneath the cryptocyst cover. (After Levinsen, 1909.) 25 tentacles. 
Genotype. — Stegcinoporella ( Membranipora ) 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, 1907, not Reuss, Lutetian of the 
Paris Basin. 
Steganoporella similis Koschinckv, 1885, Lutetian of Bavaria. 
Steganoporella ( Vincularia ) haidingeri Reuss, 1869, Priabonian of the Vicentin. 
Steganoporella (Lepralia) firma Reuss, 1867, Priabonian of the Vicentin. 
Steganoporella ( Eschara ) 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 tivo 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 polvpide-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. 
. 'Z;s=0.46-0.50 mm. 
Measurements. — a zooecia i A . 
! lz— 0.24 mm. 
Opesium 
( A<?=0.12 mm. 
Uo= 0.16-0.20 
mm. 
B zooecia 
Lz= 1.20 mm. 
fe=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 
crvptocyst 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 
