462 CRETACEOUS PELECYPODA 



numerous closely set ribs, being often interrupted by concentric lamellae of 

 growth, in the narrow ligamental furrow, and in the transversally subovate and deep 

 muscular scars. 



Locality. — East of Poodoor, in a light brown calcareous sandstone. 



Formation. — Ootatoor group. 



E. costata has been found at a great many localities in the cretaceous beds 

 of North America. Coquand transfers it to the " Campanien," but does not state 

 the reason for this stratigrapliical determination. The only European species 

 allied to E. costata is E. Overioegi, Buch ; it is a less oblique and more elongated 

 shell. 



6. ExoGYRA Tamulica, Stoliczka, PI. XLI, Figs. 2—3 ; PI. XLII, Pig. 1. 



Exog. testa elongate ovata ; valva majore, convexa, inflata, prope umbonem sessili, 

 concentrice confertim costulata, costulis undulatis, rugulosis, subnoclnlosis et mibundu- 

 latis, nonminqumn in parte suh-timbonale striis lamelliformibiis confertissimis snh- 

 stit litis ; vmbone valde intorto ; fovea ligamentali longa, marginali, curcata, profunda, 

 angnsta, postice latiuscula, infra costa acuta margiuata, et infra earn dente transverso, 

 obstuse clongato, instructa ; imjjressione nmsculari lata, sub-rotundata, supra, (vel 

 anticej, truncata, sub-centrali ; impress, pallial. dorsaliter, fseu ad marginem con- 

 vexiimj, minute crenulata ; (calvam minorem non vidij. 



A species closely allied to Ex. Foiirneti, Coq., (Mon. Ostr. cret., p. 26), but it 

 is more regularly ovate, apparently with the beaks less distinctly incurved, and with 

 the concentric rugulose ribs more distinct. The hinge is decidedly different, there 

 being in the specimens a strongly curved marginal ligamental groove, widening 

 posteriorly, and near the anterior part is a transverse blunt tooth enclosing between 

 it and the beginning of the ligamental furrow a small pit in which evidently a 

 tooth of the other valve fits, quite similar to that in Ex. ostracina ; the muscular 

 scar is subccntric, a little nearer to the beak than to the posterior margin ; it is 

 roundish, -ndth a truncate edge anteriorly, or above. In E. Fourneti the hinge-tooth 

 is represented by a long rib, and the muscular scar is placed more posteriorly, or 

 inferiorly. The upper valve has not been observed. 



Locality. — Near Arrialoor, in a pinkish calcareous rock. 



Formation. — Arrialoor group. 



7. EsoGTUA SUBOKBICULATA, Lamarck, PI. XXXV, Figs. 1 — 4. 



1802. Gryphaa suhorhiculata, Larack., Systeme des An. sans, vert., p. 398. 



1813. Griiplutcs Satisboneiisis, Scliloth., Tasch., vii, p. 105. 



1819. Gryphtea Columha, Lamck., An. .s. vert, vi, p. 198. 



1869. Odrea Ratishonoisis, Coquand, Mon. Ostr. cret., p. 121, cum syn. 



Ex. testa irregidariter sub-orbiculata, valva majore inflata, laevigata, interdum- 

 que irregulariter rugulose striata, in decUvitate antica sulco IcBvi hand jit'ocul ab urn- 

 bone ad marginem decur rente notata, nmbone valde pt^'ominente, attenuato et spiraliter 



