990 PELECYPODA. [Eulamejlibranchia. 



3. Chione Yatei, Gray, 1835. Plate 60, fig. 11. 



Venus Yatei, Gray, Yate N.Z., 300; Dieff. N.Z., 250; Hanley, Cat. Rec- 

 Biv. Shells, 112 ; Conch. Icon., xiv, f. 84. F. (Anaitis) Yatei, Gray, 

 Crit. List, 45; Ereb. & Ter., ii, 0, pi. 3. f. 11. Chione Yatei, Gray, 

 (J.M.M., 69 ; Button, J. de Conch., xxvi, 49 ; M.N.Z.M., 147. Anaitis 

 Yatei, Gray, Index, 89. Venus calcaria, Gould, P. Bost. S.N.H., iii. 

 1850, 277 ; U.S. Expl. Exp., xii, 423. Venus Lucasi, Hombron and 

 Jacquinot, Voy. P.S., Zool., v, 115, pi. 20, f. 1. 



Shell ovate, subquadrate, solid, moderately convex, yellowish- 

 brown, with thin, erect, concentric lamellae, angled posteriorly. Beaks 

 approximate, slightly raised, incurved and turned forwards, with a 

 posterior angle. Anterior end short, about one-fifth of the length, 

 narrowly convex, the dorsal margin subvertical, slightly excavated ; 

 posterior end truncated, the dorsal margin somewhat convex, very 

 little descending ; basal margin regularly rounded, lightly angled on 

 meeting the posterior margin. Lunule long, lanceolate, laminar, the 

 right half larger. Escutcheon depressed, lozenge-shaped, finely striated. 

 Sculpture consisting of distant (12 to 16 on adult shells), thin, erect, 

 concentric laminae, wavy and laciniate on the posterior half of the 

 valves, the interspaces with fine growth-lines and faint radiate striee. 

 Colour yellowish-brown, of a deeper, sometimes pinkish, tint anteriorly. 

 Interior white, porcellanous. Margins finely crenulate. Hinge : 

 strong, arcuate ; right valve with 3 cardinals, the anterior tooth 

 short, vertical, thin ; the second longer, oblique, strong, grooved ; 

 the posterior cardinal long, horizontal, grooved ; left valve with the 

 anterior cardinal subvertical, long and narrow ; the medium tooth 

 very stout, triangular, bifid ; the posterior cardinal horizontal, long 

 and thin. Ligament strong, deep-set, extending from the beaks to 

 the end of the hinge -plate. Adductor - scars subequal, both oval. 

 Pallial sinus moderately deep, free, triangular, with a blunt apex. 



Length, 55 mm. ; height, 49 mm. ; diameter, 27 mm. 



Type in the British Museum. 



Hab. North and South Islands, but rare in the South ; on sandy 

 bottom between tide-marks and in deeper water. Kermadec Islands 

 (Captain Bollons). 



Maori. Pukauri (teste Hutton). 



Fossil in the Pliocene. 



Sect. 3. CHAMELEA, Morch, 1853. 



Chumelea, Morch, Cat. Yoldi, ii, 1853, 23. Type : Venus gallina, L. Ortygia, 

 Brown, 1827 ; not Boie, 1820. Hermione, Leach, 1852 ; not Blainville, 

 1828. Orthygia, Morch, 1853. Chamelcea, H. and A. Adams, 1857. 

 Murcia (part), Riimer, 1857 ; not Koch, 1835, and probably Parvivenus 

 Sacco, 1900. 



Sculpture of narrow, close concentric waves or low lamella*, without 

 distal lamellation or radial sculpture ; teeth entire ; ligament ex- 

 posed ; the escutcheon and lunule smooth. The siphons are partly 

 united. (Ball.) KEY T0 SpECIES 



A. Shell globose, the lunule broad and short, cordate . . . . crassa. 



B. Shell compressed, lunule narrow and long, lanceolate . . . . mesodesma. 



