NO. 5 RHYNCHONELLOID BRACHIOPODS — COOPER 6j 



Hemithiris dibbleei Hertlein and Grant (1944, p. 46). Eocene of 

 California. No details of the interior of this species are given but it 

 is semicostate. In exterior view it accords with Plicirhynchia but this 

 is a much younger genus located in a completely different f aunal realm. 



Hemithiris reagani Hertlein and Grant, (1944, p. 54). Oligocene, 

 California. This species is also semicostate like that above and might 

 be referable to Plicirhynchia, but no details of the interior are known. 



" Rhynchonella" supraoligocaenica Gorges (1952, p. 5). This spe- 

 cies is from the upper Oligocene of Germany. It is a large, smooth 

 form suggestive of Aphelesia bipartiia. The interior is, however, 

 unknown and the species cannot be assigned with confidence. 



"Rhynchonella" valdiviae Helmcke (1940, p. 290). This species is 

 found near New Amsterdam in the south-central part of the Indian 

 Ocean. It resembles Compsothyris in form, ornamentation, and beak 

 characters. The color is brownish gray and the shell transparent as in 

 Compsothyris. Dental plates are present in the pedicle valve. The 

 cardinalia consist of spoon-shaped, curved crura truncated at the end. 

 The brachial valve is provided with a "very weak median-septum, the 

 front end of which is about even with the ends of the crura. The 

 septum is highest in the middle." The figure given by Helmcke (fig. 

 37) does not show the septum clearly. The species strongly suggests 

 Compsothyris, but it is not possible to be sure until better details of the 

 interior are known. 



This species also suggests Hemithyris striata Thomson from off 

 Shackleton Glacier, Davis Sea, Antarctica, by its rounded outlines and 

 fine costellae. These two species are assigned to Compsothyris with 

 a query. 



REFERENCES 



Acer, D. V. 



1957. The true Rhynchonella. Palaeontology, vol. 1, pt. 1, pp. 1-15, pis. 1,2. 

 Allan, R. S. 



1938. A new genus of Tertiary rhynchonellids (Brachiopoda) from Pata- 

 gonia. Rec. Canterbury (N.Z.) Mus., vol. 4, No. 4, pp. 199-201. 

 1940. Studies on the Recent and Tertiary Brachiopoda of Australia and 

 New Zealand. Pt. 2. Rec. Canterbury (N.Z.) Mus., vol. 4, No. 6, 

 pp. 277-297, pis. 35-37. 

 Arcellin, F., and Roche, P. 



1936. Les brachiopodes bajociens du Monsard. Trav. Lab. Geol. Fac. Sci. 

 Lyons, fasc. 30, Mem. 25, pp. 1-107, pis 1-19. 

 Bittner, A. 



1890. Brachiopoden der Alpinen Trias. Abhl. K. K. Geol. Reichsanst., Bd. 



14, pp. i-iv, 1-325, pis. 1-41. 

 1892. Brachiopoden der Alpinen Trias. Nachtrag I. Abhl. K. K. Geol. 

 Reichsanst., Bd. 17, Heft 2, pp. 1-88, pis. 1-9. 



