381 CRETACEOUS PELECYPODA 



3,1,._7>. i?y.«('e;7«, Galjb., (Pal. Calif., i, p. 188, and vol. ii, p. 195,) is from California. In 

 vol. ii, p. 26S, an undetermined species is noticed by the same author from Mexico. 

 35._p. minuta, Gabb, Proc. Acad., Phil., 1860, p. 118. 

 30-39. — Pinna complauala, arata, laticoslata, ititumescens and conmhnna are from Southern India. 



PINNA, Linne, 1758, (see p. 382). 

 1. Pinna complanata, Stoliczka, PI. XXIV, Eigs. 3-4. 



1846. Pinna restiiuta, Honingh. apud Forbes, Trans. Geol. Soc, Loud., vii, p. 153, — iion eadem Honingh. 

 apud Go\i!ii.^cretacea, Schloth. 



Pinna testa elongato trUjona, margine dorsali et ventrali angiilo 33° ab apice 

 cUvergentibus, valvis aiit compressiusculls aut lente convexis, medio in parte antet^iore 

 longltudinaliter sulcatis, in posteriore fissls, dimidio superiore, aut dorsale, cosUs 5-6 

 longitiidinalibtis, interspaciis diiplo latioribus, paido concavis, separatls, parte inferiore 

 ad medium costis 3-4 similibus et ad marginem ventralem rugis concentricis ornata. 



The ornamentation of this species with the shghtly prominent and rather 

 distant ribs very much resembles that of the European Finna cretacea, and frag- 

 ments of it have been considered by Eorbesas belonging to this species, but the 

 Indian fossil is much more widely triangular than the Eiu-opean. The valves 

 are along the middle line from the apex entire, and generally slightly grooved ; 

 approaching the middle, and further on, they are fissured. 



Localities. — Koloture, Anapaudy, Alundanapooram, in brownish sandstone. 



Formation. — Trichinopoly group. 



2. Pinna aeata, Forbes, PI. XXIV, Eig. 5, PI. XXV, Eig. 1, PL XXVI, Fig. 5. 



1846. Pinna arata, Porb., Trans. Geol. Soc., Lond., vii, p. 153, pi. xvi, fig. 10 — eadem auctorum. 

 „ Pinna decussata, Goldf., apud Forbes, ibidem p. 153. 



P. testa lanceolate trigona, margine dorsali cum ventrali angulum fere 25° ad 

 apicem formante, plus minusve inflata, valvis ad medium carinatiset in parte posteriore 

 fissis, dimidio superiore, vel dorsale, ntriusque valvce costis 7-9, iu spieciminibus adultis 

 postice costulls tenuiorlbus alternantibus ornato, dimidio biferiore ad medium 3-5- 

 costato, prope marginem ventralem concentrice eleganter striato et plicato. 



This species is very closely allied to the Eviropean Finna decussata, and some 

 larger fragments of it have been referred by Forbes to that species. The principal 

 distinction between the two is the presence of intermediate ribs on the dorsal or 

 upper halves of each valve in the Indian species. I have not observed these in the 

 true Finna decussata, but if they do occur, there would hardly be sufficient ground 

 for separating the two shells, as the only other character of note consists in the 

 fineness of the strige of growth crossing the longitudinal ribs in P. arata. 



LocalUy. — Anapaudy, Serdamungalum, Koloture, in brownish sandstone. 



Formation. — Trichinopoly group. 



