OF SOUTHERN INDIA. 189 



name Isocardia must be regarded as synonymous with Gray's Acanthocardia, Card, 

 echinatum being figured by the former as one of the type species ; the other two 

 of Klein's figures will scarcely admit of any reliable identification. For what 

 reason Eomer (Mart, and Ohem. Conch.-kab., vol. x, pt. iii, p. 5,) increased 

 the number of synonyms by proposing in 1869 for Glossus cor the name TycTiO' 

 cardia it is really diflficult to understand. 



11. Glossocardia, StoL, 1870. Shell elongately trapezoid, sub-yentricosCj 

 concentrically striated, beaks tumescent, obtuse, close together as in Trapezium ; 

 ligamental furrow narrow and long, as in Glossus; hinge with two cardinal and 

 one posterior lateral tooth in each valve ; the supero-posterior cardinal teeth 

 generally are more or less distinctly bifid, at least the one in the right valve, which 

 has anteriorly a thin, sub-obsolete prolongation bent downward; it is separated 

 from the inferior cardinal and bluntly tubercular tooth by a deep sickle-shaped groove 

 in which fits the similarly shaped antero-inferior cardinal tooth of the left valve ; 

 this tooth is provided on the upper side with two grooves, their distance being equal 

 to the width of the pit into which the antero-inferior tooth of the right valve fits. 

 I consider as the type of this genus Oypricardia ohesa, Eeeve, (vide his Monograph 

 of Oypricardia in Conch. Icon., vol. i). My friend, Dr. J. B. Baxter, has 

 collected a few valves of this rare species at Barkley Island near Port Louis 

 (Mauritius), the locality of the species having been previously unknown. In 

 general character this shell closely resembles a Trapezium^ being elongated 

 and having the beaks close to each other, but it has not the characteristic radiating 

 striae of that genus, and the hinge shows most marked differences. The 

 two cardinal teeth and the somewhat remote posterior lateral tooth readily indicate 

 a greater relation to Glossus than to Trapezium; and the anteriorly produced 

 and downward bent portion of the upper cardinal tooth of the right valve places 

 it near Veniella f== Venilia, Mort.), while the sickle-shaped form of the antero- 

 inferior tooth of the left valve distinguishes it readily from that genus. 



Another typical species of Glossocardia is the tertiary Isocardia suhtransversa^ 

 d'Orb., (see Homes' MolL d. Wiener Beckons, vol. ii, p. 166, pi. 20, fig. 3); it 

 differs from the recent species by a distinctly margined lunula, and by being less 

 high posteriorly than anteriorly. A third species appears to be Zittel's Isocardia 

 planidorsata, (Bivalven der Gosau-gebilde, Denksch. Akad., Wien, vol. xxiv, pt. ii, 

 1865, p. 140, pi. 5, fig. 4), though it also exhibits great relation to Veniella 

 proper. Cyp. crassidentata of the same author is also doubtful. There will no 

 doubt in time be several other fossil species shown as belonging to Glossocardia, 

 when their hinge-teeth have been carefully studied and compared with the typical 

 forms. 



12. Veniella, Stol., 1870, (^T^^^ifo'a, Morton, 1834, Synop. org. rem. of the 

 cret. group of U. States, p. 67, not id. Dupouch., 1829, Alder and Hanck., 18M, 

 et alii). Shell ventricose, inflated, with the beaks outwardly incurved, more or less 

 distant, a long narrow ligamental furrow running from them posteriorly, situated 

 above strong fulcra; hinge with two cardinal and one posterior lateral tooth in 



J ., , " ^ ' '■ ,/V257, ' ■ 



