OF SOUTHEEN INDIA. 249 



easier to settle this question, if Deshayes had in such a case as this pointed out 

 the species to which he particularly refers, for, as the statement now stands, it 

 seems to be only a guess. Tliere are no doubt several of Agassiz' MactromycB in 

 external form almost identical with Sjportella, but they again so perfectly resemble 

 other species in wliich the muscular impressions and pallial sinus indicate a generic 

 difference, that it does not appear at all probable that any of them belong to 

 Sportella, Such is at least the opinion which one is forced to accept by a 

 comparison of Agassiz's drawings; the examination of original specimens may, of 

 course, lead possibly to different results. Deshayes further states that Sowerby's 

 CorUs Icevis (Min. Conch., vi, pi. 580,) is a Sportella, Sowerby shows in the only 

 specimen which he examined a large anterior lateral tooth and the posterior is 

 said to have possibly been worn away, but even should this not have been the case, 

 the species could not belong to Sportella ; it may, however, be a CorUcella, 



11. Sphcsrella, Con., 1838, (Tert. foss., p. 17, and Journ. Acad. N. S., Phil, iv, 

 p. 280). Shell rounded, tumid, thin; hinge with two cardinal teeth in each valve, 

 the posterior one in the right valve broad, bifid, parallel to the hinge margin, in 



the left single, but equally elongated; type, Sph. sub-vexa, Con., from tertmry/ i^Lo^^tc, 

 deposits ; the genus also occurs in cretaceous and older mesozoic deposits, but 

 appears to be very scarce. Laube described one species, i^^ci/za (^/^(?(?p5, from the 

 St. Cassian beds (vide Denksch. Akad., Wien, xxv, pt. ii, p. 36, pi. 15, fig. 5). 

 Even some of the palaeozoic Lucince may belong to the genus. Conrad and others 

 class it near JDiplodonta, but the prolonged posterior teeth appear to indicate a 

 greater relation to the various cobbing than to the TIngulinid^. 



b. 8uh-famil?/,—L VCININJE. 



12. TUlis, Eischer, 1864, (Journ. de Conch., ix, p. 345). Shell ovate, higher 

 than long, inflated, thin, finely concentrically striated and with a posterior dupli- 

 cature extending from the beaks; hinge edentulous, lunula small and very deep, 

 forming a kind of a roundish or spoon-shaped process below the beaks ; muscular 

 impressions rounded. Type, PA. Cumingii, Eisch., from the Moluccas. 



13. Cryptodon, Turton, 1822. Shell sub-orbicular, somewhat higher than 

 long and with a deep groove extending from the beaks to the postero-inferior 

 margin, thin, lunule distinct ; hinge with a single cardinal tooth in the right valve ; 

 ligament thin, linear, marginal ; muscular impressions roundish oval. Type, (7. flexuo- 

 sus, Mont. The few species known live in the northern seas and in deep water. 



14. Lucina, Brug., 1792. Shell rounded, sub-orbicular, moderately com- 

 pressed, or more or less inflated and solid, ligament situated in a deep groove, some- 

 times nearly internal ; hinge with two cardinal and two lateral teeth, one or the 

 other often becoming partially or wholly obsolete ; anterior muscular impression 

 large, elongated, more or less prolonged towards the centre of the valves ; posterior, 

 oval, sub-marginal ; pallial line distinct, sometimes partially or locally interrupted ; 

 internal layer of shell within the pallial line distinctly rugose, opaque; lunule 

 usually deeply excavated. 



