666 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
sometimes regularly rectilinear; they never commence with an isolated zooecium. 
The distance apart of the zooecia in quincunx is from 0.40 to 0.50 mm. 
| Maximum width of zoarium 1.6 mm. 
Measurements. — Length of tube 0.40-0.50 mm. 
[ Diameter of peristome 0.10-0.12 mm. 
Affinities. — In the arrangement of its tubes and in the aspect of the zoarium, 
this species much resembles Proboscina colubra / it differs from it in its much smaller 
micrometric measurements. 
Occurrence. — -Upper Jacksonian (Ocala limestone) : Chipola River east of 
Marianna, Jackson County, Florida (rare). 
Cotypes. — Cat. No. 65290, U.S.N.M. 
PROBOSCINA RECTALINEA, new species. 
Plate 152, figs. 3-7. 
Description. — The zoarium is multiserial and incrusts shells in linear branches. 
The tubes are little distinct, cylindrical, arranged in quincunx, feebly striated trans- 
versally. The peristome is thin, salient, orbicular, somewhat oblique. 
I Maximum width of zoarium 0.80 mm. 
Length of tube 0.35-0.48 mm. 
Diameter of peristome 0.12 mm. 
Variations. — The first branches are triserial ; they never start with an isolated 
zooecium. The branches are directed in a straight line with remarkable regularity. 
The protoecium is orbicular and very small; its diameter is 0.12 mm. 
Affinities. — The tubes are of the size of those of P roboscina exigua , but the 
present species differs from it in its much more salient peristome, and in its zooecia 
arranged in more crowded quincunx. 
Occurrence'. — Vicksburgian (Marianna limestone) : Salt Mountain, 5 miles 
south of Jackson, Alabama (rare). 
Cotypes.— Cat. No. 65376, U.S.N.M. 
PROBOSCINA CONVENIENS, new species. 
Plate 152, figs. 10-12. 
D escription. — The zoarium is multiserial and incrusts shells; the branches are 
arranged symmetrically on each side of the ancestrula; they have the form of an 
elongate palm leaf. The tubes are indistinct, arranged in regular quincunx. The 
peristome is thick, salient, orbicular. 
1 Maximum width of zoarium 1.00 mm. 
Length of tube 0.30 mm. 
Diameter of peristome 0.12 mm. 
A-ffnities . — This species much resembles L>iaperoecia clava , new species, but 
differs in its much thicker peristome and in its micrometric measurements. We be- 
lieve that the discovery of the ovicell of this species would classify it in Diaperoecia. 
