OP SOUTHEEN INDIA. I45 



pallia! sinus extending horizontally, or with the point bent downwards. The type 

 of this genus is Linne's Venus (Tapes) literata, and I think it quite unjustifiable 

 to introduce another quasi-generic name for it as proposed by Eomer. 



^a. Amygdala apud Homer (Guneus, da Costa, apud H. and A. Adams). 

 Shell in form resembling Tapes, but the surface is radiately ribbed, and the inner 

 edge shows sometimes indications of a fine crenulation ; pallial sinus horizontal or 

 slightly ascending, obtusely rounded at the end. 



The type of this is Linne's T. decussata, I am not acquainted with the 

 reference Guneus reticulatus, daCosta, quoted in Reeve's Monograph among the 

 synonyms of this species. H. and A. Adams use the name Gufieiis as sub-generic 

 of Tapes for the present group of shells. The omission of giving the date and 

 reference so as to be able to trace the signification in which the genus was 

 proposed is again a great bar on this occasion. Certain it is that daOosta in 

 his - Elements of Conchology," (1774, p. 270, pi. vi, fig. 5,) applied the name Guneus 

 to a fossil Trigonia, and in no way to a shell allied to the Veneribm. Mlihlfeld 

 and others used the same in a different way, and it would probably be best not to 

 bring it up again, for it would now only cause confusion. 



45. Myrsus, H. and A. Adams, 1857, (" Genera SuppL, p. 660). Shell like 

 Tapes, but the surface covered with corrugated concentric strise. Type Venus 

 corrugata, Deshayes. 



5. Baroda, Stoliczka, 1870. Shell very much elongated, very inequi- 

 lateral, with sub-parallel upper and lower margins, laterally compressed, pallial ii-^^j^^^i 

 sinus moderate, horizontal or nearly so, obtuse at the end; hinge with three ^r ^^ W; ~ 

 cardinal teeth in each valve, the posterior of which is very much elongated and --^(St^^^t 

 sometimes longitudinally furrowed ; the two other teeth sometimes appear as one "' ^''^'^^J.&i 

 widely bifid tooth ; surface of valve smooth, only with concentric stri^ of growth. 

 (Type Venus f TapesJ fragilis, d'Orb., from cretaceous rocks. 



6a. Icanotia, Stoliczka, 1869. Eorm similar to the last, inner edge of 

 the shell anteriorly somewhat thickened, surface covered with radiating stri^ and 

 ribs, strongest on the posterior upper slope. Type FsammoUa impar, Zittel, 

 {YidiQ posteaj . 



Under the two above names, the second of which is probably only to be 

 regarded as sub-generic, I unite a number of fossil, chiefly cretaceous, species 

 which have been up to the present partially referred to Fsammobia, partially to 

 Tapes, Erom the former they differ widely by the character of the hinge-teeth, 

 as I had already (p. 114) occasion to remark. They are, however, certainly 

 closely related to the latter, but of all the numerous species of recent tapesin^ 

 which I had examined, I never found such a difference in the length of the hino^e- 

 teeth as I have noticed above ; the posterior tooth being, namely, very elongated, 

 parallel to the ridge, or fulcrum, which supports the ligament, while the two 

 anterior cardinal teeth, situated directly under the umbones, are small and 

 thin: only very rarely is the most anterior or sub-lunular tooth also somewhat 

 elongated. 



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