1282 



Genus CYPRIMERIA Conrad. 



Cyprimeria Conrad, Proc. Acad. Nat. Sci. Phila. for 1864, p. 212 (C. excavata Morton) ; 

 Am. Journ. Conch., ii., p. 102, 1866; v., p. 98, 1869; Stoliczka, Cret. Pel: India, p. 

 157, 1871; Tryon, Syst. Conch., iii., p. 180, 1884; Fischer, Man. de Conchyl., p. 1082, 

 1887. 



fCyclothyris Conrad, in Kerr, Geol. Rep. N. Car., App., p. 8, 1875 ; C. carolinensis Con- 

 rad, loc. cit., pi. ii., fig. 3, 3a, 1875 ; not Cyclothyris McCoy, Brachiopoda, 1844. 



This genus is characteristically Cretaceous and has a suborbicular shell, 

 feebly concentrically sculptured, rather heavy and moderately convex, without 

 any circumscribed lunule or escutcheon, the ligament external but set in a 

 depressed area, on each side of which the valves rise to a rounded dorsal limit 

 but without becoming keeled. The internal margins of the valves are smooth. 

 The hinge formula is L - IOIOI - . The first anterior left cardinal and the anterior 



R. oioioi. 



two right cardinals are entire, the others grooved or bifid. There is no trace 

 of any lateral tooth. The pallial line is almost simple ; a slight flexuosity, as 

 in Circe, alone represents the sinus. It is obvious that the animal must have 

 had very short siphons, if any, and cannot have been closely related to Dosinia, 

 as supposed by Stoliczka. The Indian species with which Stoliczka was 

 familiar are not typical representatives of the genus, and appear to belong to 

 a group to which Conrad gave the preoccupied name of Cyclothyris. This 

 has the dental formula of Cyprimeria except that the middle left and posterior 

 right cardinals are the bifid ones, and the pallial sinus, though not deep, is well 

 developed and ends in an almost rounded arch in front. Stoliczka describes 

 all his Indian species as more or less deeply sinuate, and therefore they must 

 agree with Cyclothyris Conrad. C. carolinensis Conrad and C. Oldhamiana 

 Stoliczka illustrate this form, while C. alta Conrad and C. discus Matheron 

 typify the original Cyprimeria. To Cyclothyris Conrad, not McCoy, I have 

 given the name Cyclorisma in Proc. U. S. Nat. Mus., xxvi., p. 357, 1902. 



Genus THETIRONIA Stoliczka. 

 Thetis Sowerby, Min. Conch., vi., p. 19, pi. Dxiii., 1826, T. major Sowerby, loc. cit., p. 20, 



pi. Dxiii., figs, i to 4; not Thetis Oken, Lehrb. d. Naturg., pp. 278, 280, 1815 (= Tethys 



Cuvier, 1800), nor Thetis C. B. Adams, 1845. 

 Thetironia Stoliczka, Cret. Pel. India, p. 158, 1871 ; Dall, Proc. U. S. Nat. Mus., xxvi., p. 



357, 1902. 

 fThetiopsis Meek, Pal. Upper Missouri, p. 191, 1876; T. circularis Meek and Hayden, 



loc. cit., p. 190. 

 fTethiopsis Fischer, Man. de Conchyl., p. 1085, 1887. 



