The Austral Rhynchoneilacea. 189* 



Dimensions. — Length, 10 mm.; breadth, 10.5 mm.; thickness, 7 mm. 

 Occurrence. — (?) Oligocene. Type locality, Everett's Limestone 

 Quarry, Kakanui, Oamaru District. 



Acknowledgments. 



In the preparation of this paper we desire to express our great 

 obligations to Dr. Allan Thomson, M.A., Director of the Dominion 

 Museum, Wellington, who has sent us on loan a most representative 

 collection of New Zealand fossil rhynchonellids, and has presented 

 the topotype of Mutton's T. squamosa to the National Museum. In 

 addition he has taken a lively interest in our work, and we have had 

 from him many valuable suggestions. 



Our acknowledgements are also due to Mr. J. A. Kershaw, F.E.S., 

 Curator of the National IMuseum, for kindly supplying us with the re- 

 cent examples of Hemitliyris pslttacea and T. nigricans, from the 

 zoological collections. 



To Mr, F. A. Cudmore our best thanks are due for his kindnessi- 

 in placing in our hands the whole of his fine collection of rhynchonel' 

 lids, for use in descriptive work; and for donating the specimens we- 

 have figured, to the National Museum collection. 



We have also made use of a topotype of T. squamosa kindly sent 

 by Mr. P. Morgan, Director of the Geological Survey of New Zealand, 

 who has also supplied localities of New Zealand specimens in the^ 

 National Museum, and to him our thanks are due. 



We express our best thanks to Mr. F. A. Singleton, M.Sc, for 

 bringing under our notice several references. 



To. Mr. H. Finlay we are indebted for a collection of rhynchonellids 

 from Target Gully, New Zealand, which has been useful in our 

 descriptive work. 



V,— Summary. 



1. — The austral forms of the " nigricans series,*' to which we give the 

 new generic term, TegulorhyncMa, constitute a zoological group 

 distinct from the boreal generic type, Hemitliyris. 



2. — The examination of the more spinous members of the genus Tegu- 

 lorhynchia, including T. coelospina and T. doederleini, confirms the 

 assumption that they have no relationship with the spinous genus, 

 Acanthothyris, D'Orbigny, of Jurassic age, but are variants, not 

 necessarily senescent, in which the tegulation is carried to an 

 extreme in the form of redundant ornament. 



3. — From an examination of the Australian Mesozoic rhynchonellid 

 fauna, it is postulated that, the Cainozoic species of the Tegulo- 

 7'hynchia series have probably evolved from a Jurassic form like 

 that of Burmirhynchia, Buckman, and without the intervention 

 of the Gyclothyris type, which seems to have been entirely con- 

 fined to the Cretaceous of Europe. 



