214 THE VOYAGE OF H.M.S. CHALLENGER. 



Habitat. — Station 162/ off East Moncoeur Island, Bass Strait, in 38 to 40 fathoms. 

 This pretty species is remarkable for the depressed closely-packed costse, and the very 

 numerous narrow transverse tubercles upon them. 



Cardita insignis, n. sp. (PI. XV. figs. 3-36). 



Testa parva, alba, mediocriter convexa, subcircularis, suba^quilateralis, liris confertis, 

 radiantibus aliisquc concentricis magis remotis concinne caneellata, plicis radiantibus 

 3 to 4 utrinque undulata. Umbones parvi ad apicem Iseves. Margo valvarum 

 iuternns utrinque fortiter denticulatus, inferne simplex, acutus. Dentes cardinales duo 

 in utraque valva, quorum auticus valvse sinistrse et posticus dextrse crassi, triangulares. 

 Cicatrices elongatse, et linea pallii simplex. Ligamentum marginale. 



This little species is as high as or even a trifle higher than long, fairly convex, rather 

 circular, equilateral, and for so small a shell not very thin. It is white and minutely 

 cancellated with numerous close-set very fine radiating lirse, and other concentric ones, 

 which are, however, much farther apart. Besides this ornamentation the valves exhibit 

 on each side three or four radiating depressions or folds, which impart a strongly dentate 

 character to the inner margin, which is smooth elsewhere. The beaks are small, smooth 

 at the tip, which inclines over towards the front. The dentition is strong. In the right 

 valve there are two cardinal teeth, the posterior being much thicker than the other, from 

 which it is separated by a triangular pit. The left valve also has two cardinals, but in 

 this instance the anterior, immediately beneath the apex of the umbo, is far the stouter, 

 the posterior being oljlique and slender. The muscular scars appear to be rather long on 

 both sides, and the pallial line simple. 



Length 3i mm., height 3^, diameter 2^. 



Habitat. — Station 188, south of New Guinea, in 28 fathoms; green mud. 



This species will readily be recognised by the remarkable lateral sculpture and the 

 strongly dentate margin. It is a small Lncina-like shell, but judging from the hinge- 

 characters belongs to the genus Cardita. 



Cardita (Thecalia) concamerata (Chemnitz). 



Gliama concamerata, Chemnitz, Conch. -Cab., vol. vii. p. 138, pi. 1. fig. 506. 



Chama concamerata, Wood, Ind. Test., pi. ix. fig. 15. 



Cardita concamerata, Bruguiere, Ency. M6th., p. 138, pi. ccxxxiv. fig. 6. 



Cardita concameirUa, Reeve, Conch. Icon., vol. i. figs. 42, a, I). 



Cardita concamerata, Krauss, Siidafr. Moll., p. 13. 



MytiJlcardia [Thecalia) concamerata, Chenu, Man. Conck, vol. ii. p. 136, figs. 652 and 654. 



Mi/tilicardia {Thecalia) concamerata, H. and A. Adams, Genera Eec. Moll, vol. ii. p. 489. 



Tliecalia macrothcca, Adams and Angas, Proc. Zool. See. Lond., 1864, p. 39. 



Habitat. — Sea Point, Cape Town. 



