384 CEETACEOIJS PELEOYPODA 



34. — F, Brewerii, Gabb._, (Pal. Calif.^ ij p. 188^ and vol. ii^ p. 195^) is from California. In 

 vol. \ij p. 268^ an undetermined species is noticed by the same author from Mexico. 

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

 36-39. — Pinna com]^^lanata , arata, laticostata, intumescens and consohrina are from Southern India. 



■ PINNA, Linne, 1758, (see p. 382). 

 1. Pinna complanata, Stoliczka^ PL XXIV, Pigs. 3-4. 



1846. Pinna restituta, Honingh. apud Forbes, Trans. Geol. Soc, Loud., vii, p. 153, — non eadem Honingli. 

 apud Gr old f. =: cretacea, Schlotli. 



Pinna testa elongato trigona^ margine dorsali et ventrali angulo 33° ah apice 

 divergentibus, valvis ant compressiusculis aut lente convexis^ medio in parte anteriore 

 longitudinatiter sutcatis^ in posteriore fissis, dimidio superiore, aut dorsale^ costis 5-6 

 longitiidinatihtis, interspaciis diiplo tatioribus, pauto concavis, separatis, parte inferiore 

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



The ornamentation of this species with the slightly prominent and rather 

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

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

 Indian fossil is much more widely triangular than the European. 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, PL XXV, Eig. 1, PL XXVI, Eig. 5. 



1846. Pinna arata, Forb., 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 carinatis et in parte posteriore 

 fissis, dimidio superiore, vel dor sale, utriusque valvce costis 7-9, in speciminibus adultis 

 postice costulis tenuioribus alternantibus ornato, dimidio inferiore ad medium 3-5- 

 costato, prope marginem ventralem concentrice eleganter striato et plicato. 



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

 larger fragments of it have been referred by Eorbes 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 striae of growth crossing the longitudinal ribs in P. arata. 



Locality,— Aim^^uAj, Serdamungalum, Koloture, in brownish sandstone. 



Formation, — Trichinopoly group. 



