404 CRETACEOUS PELECYPODA 



entire, posterior wing agrees with Fseudo-monotis, but tbe usually characteristic 

 radiating ribs are absent, the surface being marked with thinner and thicker 

 strite of growth. It seems much more probable that the shell belongs to the 

 present genus than to Aucella, because this last never has a distinct posterior wing. 



Locality. — Rajah-Choultry, in a conglomeratic rock, with the last named 

 species. 



Formation. — Arrialoor group. 



AUCELLA, Keyserling, 1846, (see p. 390). 



Atjcella pakva, Stoliczka, PI. XXXIII, Pigs. 2-3. 



Anc. testa late et pariim oblique ovata, imrvay tenui, snb-lcevigata, stiHis incre- 

 inenti tenuibus induta, valva sinistra convexiore, mnbone valde prominente et incurco 

 instructa ; valva dextra planiuscula, umbone tmnidulo ; utraque j)ostice bremssime 

 et indistincter alata, v. sinistra auricula antica brevi trianyidari prcedita, infra 

 aiiriculam emarginata. 



A small but typical species of an Aucella, with a very thin and smooth shell. 

 The specimens are often very much compressed and deformed by pressure of the 

 surrounding rock. 



Locality. — Odium, in a light brown, soft, earthy rock. 



Formation. — Ootatoor group. 



AVICULA, Klein, 1753, (see p. 391). 



AvicuLA [Meleagbina] nitida, Porbes, PI. XXIV, Figs. 6—8, and 



PL XXXVIII, Pigs. 11-12. 



1846. Avicula nitida, Forbes, Trans. Geol. Soc, Lond., vii, p. lo\,—eadem auctorum. 



Avic. [Ifeleag.'] testa oblique sub-tetragona, equivalvi, moderate tumida, in- 

 equilaterali, margine cardinali longo, recto, margine inferiore stib-rotundato, auriculis 

 unticis angMsti-s, brevioribus, tumidulis, ad terminationem suh-acutis, ea valmdce dextrce 

 od basin vix emarginata ; auricidis piosticis ab corpore testes hand distincter separatis, 

 in speciminibus junioribus postice emarginatione modica instriictis (^vide Jig. 12, 

 tab. xxxviii,) in adultis fere rectiuscule truncatis ; superficie striis incrementi sub- 

 lamellatis, tenuissimis, distantibus, nonnunquam obsoletis tecta. 



Young shells show a smaU posterior emargination, the hinge-line terminating 

 in a sharp point, but in more fully grown specimens the posterior margin becomes 

 almost quite straight, as is often the case in recent Melegrince of a similar form. 

 The anterior ears are small, tumid, and pointed, that of the right valve barely 

 emarginated below, only a very narrow byssal fissure being present. The surface 

 when well preserved shows very sharp, distant striae of growth, indicating a lamellar 



