NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
199 
tally, and enlarged proximally; the opesium is oval shaped and a little oblique. 
The length of the zooecium is 0.60 to 0.70 mm. 
Affinities . — This species may be distinguished from Ileterocella fragilis De- 
france, 1820, by its greater micrometric dimensions, its straighter zooecia, and its 
smaller septulae. 
Occurrence . — Vicksburgian (Marianna limestone) : Salt Mountain, 5 miles 
south of Jackson, Alabama (common). 
Cotypes. — Cat. No. 64251, U.S.N.M. 
Fig 52. — Famly Eucratiidae Hincks, 1880. 
A-G. Eucratea chelata Linnaeus, 1758. A. Free larva viewed in profile ; the terminal bud 
is much reduced, the aboral face well developed, and the oral face completely flat, X 75. 
B. Aboral face of larva showing the very simple terminal bud and the stomach visible even from 
the side, X 75. C. Larva, oral face, showing the trilobate form of the stomach, X 75. 
(A-C after Barrois, 1877.) c, corona; CD, digestive cavity ; est, stomach; i, aboral face; ph, 
pharynx; pi, ciliary plume; o, mouth of the gastrula ; s, oral face; sb, furrow separating the 
aboral mass and funnel-shaped side ; si, furrow separating the terminal bud and the lower por- 
tion of the aboral face; vt, terminal bud. D. Zoarium, natural size. E. Portion of a zoarium, 
X 50, showing the structure of the zooecia and method of branching (e. hr) just below the 
opesia ( ap ) and the creeping branches ( cr. br. ) given off from the sides of the zooecia ; (op) 
operculum. (After Robertson, 1905.) F. Sketch, X 50. showing ovieell (oe) on a small aborted 
zooecium. (After Hincks, 1880.) G. Anatomical structure of a zooecium. (After Milne-Ed- 
wards, 1888.) a, zooecium; b, opesium; c, opercular valve; cl, tentacular sheath; e, ciliated ten- 
tacles; f, stomach; cj, stomachic coecum ; h, anus; i, retractor muscles of the polypide. 
Family EUCRATIIDAE Hincks, 1880. • 
Zoarium forming slender, branching, phytoid tufts. Zooecia uniserial or in 
two series placed back to back ; expanding from the base upwards, with a terminal 
or subterminal and usually oblique opesium. Neither avicularian nor vibracular 
appendages known. Ovieell globose, hyperstomial. (Robertson.) 
