78 CRETACEOUS PELECYPODA 



CEROMYA, Afjassh, 1812 (see p. 6G). 

 1. Ceromya subsinuata, Forbes, sp., PI. IV, Fig. 4. 



1846. Isocardia sithsinuata, Forbes, Trans., Geol. Soc, Lond., vii, p. 14G, pi. 17, fig. 12. 



C. testa injlata, altiori qiiam longa, tenui, concentrice sulcato-striata, rotumlalu, 

 a-quivalvi; umljonibus j^roductis, attenuatis, distantibus, antice versus valde inctirvis, 

 sulca duplici hand profnnda ah umbonibiis usque ad maryinem iwstero-wferlornii 

 dccurrente instructa ; tunula profunda, cordifurmi, marginata ; cardine edeutulo, 

 daohiis sulcis obliquis brcoibus inter umbones sitis predito. 



Height of shell : its length ... ... ... •■• I'l" 



Thiekness „ : „ ... .- ■•• ■• ^^'^ 



The external form of this species is perfectly similar to that of a Glossus Hso- 

 cardia), hut it is readily distingviished from this genus hy its tliin shell and edentulous 

 hinge, the hinge-margin heing simply a little indented at the termination of two short 

 grooves ^\hich run obliquely from the beaks posteriorly. Besides these there are two 

 other shallow grooves, which commence at the beaks and run along the posterior 

 margin of the shell to the iaafero-posterior end; the beaks are very promini'iit, 

 attenuated, and strongly incurved towards the front side ; the surface is regularly 

 concentrically striated and snlcated. 



Locality. — Pondicherry, in bluish calcareous sandstone ; rare. 



Forniutiun. — Valudayur group. 



ANATINA, Lamk., 1809 (see p. 68). 

 1. Anatina (Cercomya) arcuata, Forbes, PI. Ill, Pig. 1. 



1816. Anatina arciiaia, Forbes, Trans., Geol. Soc., Loudou, vii, p. 143, pi. 16, tig. 5. 



An. fCerc.) testa elongala, compressa, sub-a^qidlatcrali ; parte antica jjaulu 

 altiori, ad marginem sub-rotunduta ; umbonibus pjostice versus incurvatis, angnste 

 fissuratis ; parte posteriori angustata, rostriformi, prope marginem superiorem obtuse 

 bicarinata ; superjicie costis concentricis distantibus, antice elegantim arcuatis ac 

 sfriis iucrementi numerosisslmis ornata, area p>oslero-superiori solum minute striata. 



Height of shell at the beaks : its length ... .,. ... 0-24 



„ „ anteriorly : „ ... ... ..■ 03.5 



Thickness „ : „ ... ... ... 014 



The two roimded keels along the upper margin of the posterior side include 

 an area which is merely striated, while the rest of the sm'face is covered with dis- 

 tant ribs and fine striae, and this character of oi-namentation distinguishes the present 

 form from any other described from cretaceous deposits. The ribs are anteriorly 

 broadly and somewhat angularly rovuidcd, and in this respect the species again mostly 

 resembles the Jurassic An. (Cerc.J spatulata, Ag. The beaks are distinctly cm-ved 

 towards the posterior end, close together, and narro^^ly fissm-ed. 



Locality. — Pondicherry, in a pale bluish calcareous sandstone ; rare. 



Formation. — Valudayur group. 



