OF SOUTHERN INDIA. 279 



in the right valve, the auterior in the latter being often oljsolete and the 

 posterior are in both elongated ; sometimes there appears to be an indication 

 of a posterior lateral tooth ; type, A. terniinalis, Romer, from oolitic rocks. Tliis 

 genus includes a great number of chiefly lower and middle mesozoic species ; there 

 are scarcely any known from cretaceous deposits. The well known Ast. rliom- 

 boidalis, Ph., is another form of the same genus. The species have been mostly 

 referred to CarcUta, and they are the representants of 3IytilicarcUa in the astaetin.e. 

 18. GoulcUa, Adams, 1851. Shell sub-trigonal, concentrically sulcated ; 

 hinge with one sub-anterior cardinal tooth in the right and two cardinal teeth 

 in the left valve, the anterior being very small; an elongated auterior lateral 

 tooth is present in each valve ; in other respects similar to Astarte. Type, 

 G. minima, Montg. Species of GoulcUa already occur in Jurassic rocks, but 

 they are not numerous, though wherever the specimens are met with, they 

 generally are found in large numbers. 



19. Alveinus, Conrad, 1865, (Am. Jouru. Conch., i, pp. 10 and 138). " Smooth, 

 anterior, posterior and ventral margins channeled within ; hinge of right valve 

 emarginated under the apex, and having one pyramidal tooth anteriorly ; hinge of 

 left valve with a pit under the apex, and two diverging teeth anteriorly." Type, 

 Al. niinuta f-usj, Con.; this is apparently the same species which Conrad first 

 (1. cit., p. 10,) noted as A. parva f-usJ, from tertiary rocks of Mississippi. 



20. GoodalUa, Turton, 1822, emend. Deshayes, (Paris foss., 2nd ed., 

 i, p. 781; Pachyodon, Gabb, 1868, Am. Journ. Conch., iv, p. 198). Shell smooth 

 or concentrically finely striated, ovately elongated, beaks anterior or sub-anterior, 

 pointed, inciuwed, right valve with a single large median cardinal tooth, left valve 

 with two comparatively small, thin, and elongated teeth, sometimes slightly bifid, 

 and occasionally with a thin sub-obsolete lateral tooth, pallial line simple, sul)- 

 truncate posteriorly ; typo, G. miliaris, Defr., from the Paris basin. This genus 

 appears rather numerously represented in eocene rocks of Europe and America ; it 

 is probable that some of the small smooth Jurassic Astarte will also have to be 

 referred to it. 



21. Lutetia, Desh., 1860, (Paris foss., 2nd edit., i, p. 787). Shell small, ovate 

 or roundish, beaks obtusely pointed; hinge with two diverging cardinal teeth 

 and one placed longitudinally below the anterior cardinal margin in each valve. 

 Type, L. Farisiensis, Desh., from the Paris basin. Only two species are as yet 

 known. 



22. Ilicromeris, Con., 1866, (Check-list, eocene fossils ; Smith. Misc. Coll., 

 No. 200, p. 5). As the type of this genus Lea's Astarte parva and minor (Contb., 

 p. 63,) have probably to be considered. The shells are trigonal, with produced 

 somewhat attenuated rather straight beaks, ventrally rounded, slightly inflated, 

 striated, or sulcated on the surface ; the hinge appears to have two small cardinal 

 teeth in the left and one in the right valve, and one long posterior lateral tooth 

 this in each. Conrad (1. cit.) also refers Astarte minutissima, Lea, to 3Iicra//ieris, 

 but for he formerly proposed the name Fteromeris. 



3 Y 



