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Title: Rhynchonellidae of the English chalk
Author: Pettitt, N. E.
Awarding Body: University of London
Current Institution: Royal Holloway, University of London
Date of Award: 1944
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An examination has been made of the more important forms previously referred to the genus rhynchonella fischer de aldeas which occur in the chalk, with special attention to their internal structure. The morphology of the Mesozoic rhynchonellidae is discussed, and reference is made to the types of crura. Previous work on subdivision of Mesozoic form of Rhynohonella is reviewed. Reference is made to Wieniewska description of Rhynohonella; it is evident that no representatives of the genus sensu stricto have been recorded from the Chalk. The internal structure of Cyclothyris McCoy and that of Buckman's genus Stolmorhynchia to which he referred the Creteceous species invertebrates Rhynchonella sulcate (Parkinson), are discussed. Reference is also made to other Mesozoic Rhynchonellid genera including Lacunosella Wieniewska. Many Chalk Rhynchonellids were found to possess an internal structure similar to that of Stolmorhynchia Buckman and Lacunosella Wieniewska, and have been grouped in a new genus Platyrhynchia. They include the species Rhynchonella mantellianu (J. de C. Sowerby), P. wiestii (Quenstedt), R. cuvieri d'Orbigny, P. reedensis Etheridge and Terebratula obliqua James Sowerby, together with fourteen new species which are described in the paper. Rhynochonella plicatilis (James Sowerby) were found to have similar crura to those in Cyclothyris McCoy, but this median septum in the former is better developed. The species has been assigned to a new genus Cretirhynchia together with Rhynchonella Octoplicata (James Sowerby) Rhynchonella woodwardi Davidson, Rhynchonella limbata (Schlotheim) and four new species. Rhynchonella grasiana d'Orbigny, which is characterised by a well developed median septum and very fine costae is assigned to a new genus Capillirhynchia.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Biology