OF SOUTHEEN INDIA. 221 



striation is obsolete or nearly so ou the anterior declivity, and tLe ribs on the 

 posterior declivity are numerous, close together and rather indistinct; near the 

 thickened fulcra they are as usual quite obsolete. 



The species has been first figured by d'Orbigny in the Paleontology of the 

 Voyage of the Astrolabe and Zelee, but subsequently (Prod, ii, p. 212,) the same 

 author considered it as identical with the next species, from which, however, the 

 distinctions become readily apparent by a comparison of the figures. 



Localities. — Anapaudy, Alundanapooram, &c. ; not uncommon. 



Formation. — Trichinopoly group, 



4. Protocardium altum, Sotoerby, PI. XII, Figs. 1 and 3. 



1846. Cardium altum. Sow., aputl Forbes, Ti-ans., Gcol. Soc, London, vii, p. 115, pi. 15, fig. 13 — idem .auctorum. 



l?rot. testa oblique stib-trigonata, crassa, altiore qtiam longa, moderate inflata, 

 lunula paulo excavata, antice et infra ad marginem rotundata, x>ostice sub-truncata, 

 margine postico superiori oblique descendenti, recto ; superficie lamellose costtilafa, 

 costis ill parte antica obsoletis interdumque lineis filiformibus radiantibus substitutis ; 

 costulis in declivitate postica sitis confertissimis, iiiferioribus magis distinctis qxiam 

 superioribus. Cardo dentibus crassis regnlaribus instructus. 



Height of shell : its length ,.. .,, ... I'lO - 120 



Thickness „ : „ ... ... ... OSO - 0-85 



In this species the concentric lamellar ribs are about the middle of the shell, 

 obsolete ou a larger area than in the last, and moreover they are sometimes replaced 

 by more or less distinct, but usually very fine undulating radiating strioe. The lunula 

 is somewhat excavated, and the posterior hinge line particularly straight and 

 descending. The shell is, as already stated, more oblique and higher than the last 

 species, while the smaller extension of the posterior area readily separates it from 

 Frof. bisectum. 



Locality. — Monglepaudy, Odium, Ootatoor ; not common. 



Formation. — Ootatoor group. 



5. Protocardium bisectum, Forbes, PI. XII, Fig. 2. 



1846. Card, bisectum, Forb., Trans.. Geol. Soc, Loudon, vii, p. 144, pi. 17, fig. 9— idem auctorum. 



Frof. testa multo altiore quam longa, valde inflata, moderate crassa, umbonibus 

 valde prominentibus, incurvis, fere contiguis, angustis, antice leviter convexa, postice 

 truncata ; margine postero-inferiori moderate producto, lumila paulo excavata ; 

 superficie in dimidio antico concentrice subtiliter striata, in p)ost4Co radiatim 

 costellata. 



Height of shell : its length ... ... ... 1-40 



Thickness ,. : ., ... ... ... 1"13 



The great height of the shell in proportion to its length, and the whole of the 

 posterior half of the surface beiug occupied by radiating ribs, readily distinguish 



3 H 



