OF SOUTHEEN INDIA. 55 



nent ; these teeth are comparatively narrow in the young shells, but in adult 

 specimens attain an unusually large size ; pallial line unknown." Type Fs. Gabbii, 

 Rem. sp.5 from tertiary deposits of California. There is a cretaceous species 

 described by Miiller as Cardium Noggerathii, Its hinge strongly reminds one of 

 Gabb's Fseudocardium, but I have as yet only seen the hinge of the right valve, 

 and this is not sufficient for a correct generic determination. 



23. Mactrodesma, Conrad, 1868, (Amer. Journ. Conch., vol. IV, p. 247). Shell 

 sub-triangular, solid; cartilage-pit very large, projecting much beyond the lower 

 margin of the hinge ; anterior hinge-margin of right valve thick and continued 

 much beyond the beak ; hinge of left valve with a strong A -shaped cardinal tooth ; 

 lateral teeth short, thick, sub-equal ; pallial sinus narrow and deeper than in Mactra^ 

 but extending as far as the cartilage-pit ; muscular scars very large. Type Mactra 

 ponderosa, Conrad, (Eossils tert. format., 1838, p. 25, pi. 14, fig. 1), from the 

 miocene beds of Maryland. 



24. Bangia, DesmouL, 1832. Shell sub4riangular, thick, covered with a 

 brown epidermis ; hinge with two teeth in each valve, the front one of left valve 

 larger and bifid ; lateral teeth elongated, transversally striated, ligament internal, 

 situated at the upper edge of the cartilage-pit ; pallial sinus short. This is the 

 brackish representant of the mactrinje; the shell externally greatly resembles 

 some species of JJnio. The oldest species of Rangia appears to be one noticed by 

 Dunker from the Wealden deposits, as Gnathodon Valdensis, (Wealden-bildungen, 

 p. 57). 



24(^.^ Bangianella^ Conrad, 1867 (Amer. Journ. Conch., vol. iii, App. p. 30,) 

 is characterized by ''lateral teeth, straight, sub-equal, not elongated, entire;" the 

 only species is jB. trigona, Petit. 



List of cretaceous species* 



LUTBARIINM, 



For the correction of those species which have been described from cretaceous rocks under 

 the generic name of Lutraria, see Pictet^s Pal. Suisse, IV°^® Ser., 3°^^pt., p. 126. Not a single one of 

 those species has been shown to belong to this sub^family. Gabb (Palseont. of Calif., 1864, vol. 1, 

 p. 154), describes and figures a Luifafia iruncata,^R\n.Q}il appears to me to be rather a Spisula than 

 a Lutraria. 



The four species, Lutraria speciosa, ameata, navalis and tongiss'ima, (SchafheeutPs Bayern^s Leth. 

 geog., p. 172 et.) are not Lutrariaj but either Homom^ce or Panopcece. 



MAGTRIN^. 



Of most of the European species quoted by Pictet and Campiche (1. c,,p. 128, &c.,) under the 

 genus Mactra f the determination has been made from external appearance only, and in many cases 

 it still requires confirmation. The species are — 



1-7. — M. Matronensisj Valangiensis, Carteronij gauUina, sui-striata, a7igulata,porrecta, 



^ Meek (Smiths. Misc. Coll., No. 183, p. 11,) also quotes a sub-genus Perissodon. 



