18 PROCEBDIKGS OP THE MALACOLOGICAL SOCIETY. 



intusque sex costata ; costis utrinque duobus approximatis, et una 

 distincta; apertura irregulariter subcircularis. Alt. 18, diam. 

 maj. 13 mm. 



Hab. — Port Stephens, Australia (Dr. Cox). 



This very curious species, of which the generic position is doubtful, 

 is so irregular and diversiform that anything like an exact diagnosis 

 of it is scarcely practicable. The chief distinguishing character will 

 be found in the disposition of the ribs, of which both on the convex 

 and on the concave side there are three, two near together and one 

 apart ; these ribs or keels are also pretty prominent in the interior 

 of the shell and extend slightly beyond the margin. Taking the 

 twisted horn-shaped specimen for the type, I figure two others much 

 less elevated, and more obtuse. In one of these, it appears from the 

 disposition of the ribs that the apex is twisted over the reverse way, 

 and in the other laterally. The disposition of the ribs on the convex 

 side of the type shell reminds one of Amathina tricostata, Gmelin, to 

 which genus or subgenus it may possibly belong. The specimens 

 came in the collection of Dr. Cox, of Sydney, labelled " Port Stephens." 



Chlamts Smithi, n.sp. PI. I, Pigs. 6, 7. 



Testa subcircularis, sequilateralis, depressiuscula, lutea, rufo alboque 

 variegata. Valva dextra planato-convexa, costis radiantibus circiter 

 21, angustiusculis, plerumque trisulcatis, minutissime transversim 

 squamoso liratis, interstitiis profundiusculis conspicue transversim 

 acute lamellatis. Valva sinistra paulo convexior, costis sequaliter 

 numerosis, magis scabrosis, interstitiis Isevioribus, auriculis insequalibus, 

 squamoso-liratis. Alt. 17, lat. 17, crass. 6*75 mm. 



Mab. — Mauritius. 



This pretty species, sent many years ago by the late Mr. Y. de 

 Eobillard from Mauritius, has long been wanting a name. It has 

 been confounded with Chlamys nux (Reeve) and C. corruscans 

 (Hinds), but it certainly does not belong to either. C. nux has 

 a different form and general aspect ; it is much more ventricose and 

 tumid, with the sides more straightly sloping from the umbones, and 

 the depression behind the left auricle is more pronounced. I may add 

 (although colour does not count for much in determining species of 

 this genus) that the prevailing colour of C. nux is white, more or 

 less variegated with red or brown markings. Chlamys corruscans 

 (Hinds) differs somewhat inform from C. Smithi, and is longitudinally 

 lirate between the ribs, and without concentric sculpture. 



Pitaeta elata, n.sp. PL I, Pig. 8. 



Testa subtrigono cordata, tumida, crassiuscula, insequilateralis, alba, 

 concentrice irregulariter rugose striata ; latus anticum breve, superne 

 concavum, inferne rotundatum ; latus posticum arcuatum ; margo 

 ventralis rotundatus, postice leviter sinuatus ; lunula leviter depressa, 

 cordif ormis ; umbones acuti, approximati, antrorsum incurvati. Liga- 

 mentum longum, tenue, immersum. Cardo normalis. Alt. 28, 

 lat. 31 mm. 



Hab. — Off Sierra Leone (Keppel). 



