460 CRETACEOUS PELECYPODA 



numerous decussating strise ; the beak is always equally strongly incurved as in the 

 other valve. In both the pallial margin is j&nely crenulated all round, and at the 

 ventral side, where near the hinge, it is reflected over a portion of the ligamental 

 furrow and the beaks, is finely striolated. The muscular scars are irregularly 

 excentric, being situated somewhat near the ventral margin, excavated, and their 

 upper ed"-e begins almost immediately below the region of the beaks. 



The Indian specimens, in which the ribs are not present on the dorsal slope of the 

 larf^er valve, perfectly agree in general character with European ones, particularly 

 with those from the Pyrenees mountains, described by Leymerie as Exorjyra 

 ptirenaica. Even in specimens of this form, for which we are indebted to 

 Prof. Hebert, I can, however, observe an indication of slight folds or ribs on the 

 laro-er valve, and this seems to make it doubtful whether Coquand is correct in 

 all the references quoted as synonyms of the three closely allied species, Ex. 

 ostracina, (=^ auricularisj, E. Matheronana et E. plicifera. 



Localities. — Vylapaudy, south-east of Kaudoor, east of Nullaenaccary, Arria- 

 loor, Yalore, &c., &c., mostly in a softish grey sandstone, at the last named, 

 locality in a white calcareous rock. 



Formation. — Arrialoor group. 



In Europe Ex. ostracina has been found at a great number of localities, in 

 France, Germany, Sweden, Austria, Russia, &c., in upper cretaceous beds (^tage 

 Campanien of Coquand) ; in similar strata the species has also been met with 

 in North and South America, in North Africa, and in Syria and Palsestine ; in 

 India it is also a characteristic fossil of the uppermost beds of the series of 

 the Trichinopoly deposits, the Arrialoor group. 



3. ExoGYUA LACiNiATA, Nllssou, PI. XXXVIII, Figs. 1 — 3. 



1827. Chama laeiniata, Nilss., Petrsef. Suec, pi. viii, fig. 2. 

 1869. Ostrea laeiniata, apud Coquand, Mon. Ostv. cret., p. 55. 



Ex. testa irregulariter elongato ovata, vaha majore valde convexa, medio 

 longitudinaUter gibboso carinata, lateraliter prope timbonem sessili, in decUvitate 

 convexa radiatim sjxtrse crasse-costata, costis irregidaribus, ciirvatis, lamellose 

 fiodosis, ad margineni plus mimisve projicientibus ; nmbone valde intorto, nonnnnqnam 

 indistincto ; valoa minore planata ant modice concava. 



Of this interesting species only a single specinfen exists in our collection 

 from South India. The species is readily recognised by the ovate, inflated form 

 of the larger valve and by the few strong ribs which are very prominent on its 

 tipper or convex slope, while on the ventral side the shell is generally more 

 irreo-ular, being attached near the beak. Coquand ah-eady quotes this species 

 from VerdachcUum. 



Locality. — Ninnyoor, in a light brown sandy limestone. 



Formation. — Arrialoor group. 



In Europe Ex. laeiniata has been found in the upper cretaceous beds (Cam- 

 panien of Coquand) of various parts of England, France, Germany, and Sweden. 



