212 
BULLETIN 10(5, UNITED STATES NATIONAL MUSEUM. 
canal is very small; the opesium of the onychocellarium is longer than the zooecia! 
opesium, oval, the point at the top. 
M easurenients . — Opesium of 
zooecium 
Zooecium 
\ho= 0.35 mm. 
\lo= 0.25 mm. 
\Lz= 0.45-0.55 mm 
7,3=0.40-0.45 mm. 
Opesium of \lxon=0A5 mm. 
onychocellarium 1 Jon= 0.17 mm. 
fZ<m=0.75-0.90mm. 
' mvchoceilanum , .. 
J !Zuw=0.30mm. 
Affinities . — This fine species does not exhibit a polypidian convexity, which 
characteristic clearly distinguishes it from Rectonycliocella semihma / moreover, the 
point of the onychocellarian opesium is more often at the top than at the bottom. In 
the vicinity of the ancestrula the onvchocellaria are much less in width than the 
zooecia (fig. 6). 
Occurrence . — Lower Jacksonian (Moodys marl) : Jackson, Mississippi (com- 
mon) . 
Jacksonian (Zeuglodon zone) : Cocoa Postoffice, Choctaw County, Alabama 
(rare) ; Shubuta, Mississippi (rare) ; Bluff on south side of Suck Creek. Clarke 
County, Mississippi (very rare). 
Upper Jacksonian (Ocala limestone), west bank Sepulga River: Escambia 
County, Alabama (rare) ; Alachua, Florida (rare) ; nine miles north of Ocala, 
Florida (rare). 
Vicksburgian (Red Bluff clay) : Seven and one-half miles southwest of Bladen 
Springs, Alabama (rare). 
Cotypes. — Cat. Nos. 63967, 63968, U.S.N.M. 
KECTONYCHOCELLA ELLIPTICA, new species. 
Plate 33, figs. 7, S. 
Description . — The zoarium incrusts shells (Ostrea) or bryozoa. The zooecia 
are elongated, hexagonal, distinct, separated by a small furrow or thread. The 
cryptocyst is concave, deep, finely granulose, and as long as the opesium; the 
opesium is elliptical , elongated, finely crenulated ; the polypidian convexity is only 
visible in the vicinity of the ancestrula. The endozooecial ovicell is a barely visible 
convexity. The onychocellarium is straight, lozenge-shapecl, enlarged at the base; 
its cryptocyst is very small, and its opesium is oval, the point below, with a denticu- 
In ted posterior; the small distal canal often fuses with the cryptocyst of the distal 
zooecium. The ancestrula is small and exhibits a polypidian convexity. 
Measurements . — Opesia of zooecia 
Opesia of onvchocellaria^ 
( ko =0.30 mm. 
I /u=0.20 mm. 
\ hon= r 0.34-0.36 mm 
[Zcm=0.16 mm. 
Zooecia 
Zs=0.40-0.50 mm. 
Zs=0.34— 0.36 mm. 
Onvchocellaria 
\Lon= 0.60-0.70 mm. 
lZ<m=0.24 mm. 
