Doctoral Dissertations


"Free, cup-shaped colonies of cheilostomatous bryozoans, equipped with vibracula, are termed lunulitiform bryozoans. This group is found in sandy and calcareous Cenozoic deposits of the Gulf and Atlantic Coastal Plains. Cupuliform bryozoans are taxonomically distinct from, but in many ways similar to, lunulitiform bryozoans; the two groups are frequently found together.

Known lunulitiform genera of the Gulf and Atlantic Coastal Plains are diagnosed and their species described: Lunulites Lamarck, fifteen species, one new; Oligotresium Gabb and Horn, six species, two new; Discoporella d'Orbigny, two species; Cupuladria Canu and Bassler, two species; Selenaria Busk, one species; Otionella Canu and Bassler, four species, one new; and New Genus A, one new species. One cupuliform genus is diagnosed: Schizorthose-cos Canu and Bassler, four species.

Morphological terms applied to lunulitiform bryozoans are clarified. So-called "hollow" zoaria are proved to result from mode of preservation. The "Trochopora" type, or solid, zoarium is shown to be a structural variation that is not considered to be of taxonomic significance.

Various hypotheses of nodes of life and orientation are reviewed and compared with results obtained by observation of living material collected from the Gulf of Mexico. All hypotheses involving a natatory mode of life during the adult stage are discarded. Lunulitiform zoaria can exist in both apex-up and apex-down positions.

Lunulitiform bryozoans have numerous associated commensals and predators, as observed with live material. Commensal organisms include coelenterates, polychaetes, foraminifera, planarians, and other bryozoans. The major predators observed were the common blue crab and the hermit crab.

Regenerated zoaria are considered to result from breakage by predators rather than from breakage by current action..

Lunulitiform bryozoans and some cupuliform bryozoans are associated with calcareous sands deposited in shallow shelf areas with moderate current action and tropical to semitropical temperatures"--Abstract, pages ii-iii.


Frizzell, Don L. (Donald Leslie), 1906-1972

Committee Member(s)

Spreng, Alfred C., 1923-2012

Maxwell, James C.
Beveridge, Thomas R. (Thomas Robinson), 1918-1978
Proctor, Paul Dean, 1918-1999
Campbell, Robert A.


Geosciences and Geological and Petroleum Engineering

Degree Name

Ph. D. in Geology


Dr. D. L. Frizzell, Dissertation Supervisor


University of Missouri at Rolla

Publication Date



vii, 216 pages

Note about bibliography

Includes bibliographical references (pages 202-206).


© 1966 Ronald Greeley, All rights reserved.

Document Type

Dissertation - Open Access

File Type




Subject Headings

Bryozoa -- Gulf States
Bryozoa -- Atlantic States

Thesis Number

T 1885

Print OCLC #


Electronic OCLC #


Included in

Geology Commons