Panopea.] PELECYPODA. 1013 



thick and short, grooved. (For notes on the anatomy, see S. P. 

 Woodward, A.M.N.H. (2), xv, 1855, 99 P. siliqua.) 



Shell equivalve, transversely oblong, solid, gaping at both 

 ends, surface nearly smooth or concentrically striated, inequilateral ; 

 hinge formed of a single conical tooth in each valve, lodged in a 

 socket of the opposite valve ; ligament external, short and pro- 

 minent, attached to strong nymphs ; pallial line with a deep posterior 

 sinus. 



Distribution. Mediterranean, Atlantic, Cape of Good Hope, Pata- 

 gonia. Australasia. 



Fossil in the Tertiary. 



1. Panopea zelandica, Quoy and Gaimard, 1835. Plate 61, tigs. 10, a. 



Panopcca zelandica, Q. & G., Voy. Astrol., iii, 1835, 547, pi. 83, f. 7-9 ; 

 Valenciennes, Arch. Mus. Hist. Nat., Paris, i, pi. 3, f. 2 ; Conch. Icon., ii, 

 f. 9 ; Dieff. N.Z., 255 ; C.M.M., 60 ; Grit. List, 41 ; M.N.Z.M., 134 ; 

 Hutton, P.L.S. N.S.W., ix, 513 ; Index, 88. Panopea Solandri, Gray, 

 Dieff. N.Z., 255: Conch. Icon., f. 6; C.M.M., 60; Grit. List, 41; 

 M.N.Z.M., 134. 



Shell large, elonguteiy oval, inequilateral, gaping at both ends, 

 but much more posteriorly, irregularly concentrically ribbed, inflated, 

 but compressed ventrally, rather thin and fragile, white. Beaks 

 anterior, flatly raised, incurved, a little excavated in front, approxi- 

 mate. Anterior end shorter, regularly convex, gaping, the dorsal 

 margin lightly convex and very little descending ; posterior end 

 broadly rounded or truncated, the valves slightly expanded, dorsal 

 margin straight or lightly concave, horizontal ; basal margin straight, 

 rounded at both ends. Sculpture consisting of broad, irregular, 

 angularly raised concentric ribs, the interstices with fine growth- 

 lines ; at the posterior end the ribs are broad and flat. Colour cream- 

 white. Interior white, lightly concentrically grooved. Margins 

 smooth, sharp. Hinge narrow and short, with strong, short nymphs, 

 and a long, conical, erect tooth in each valve. Ligament external, 

 short, very prominent. Adductor-scars unequal, not much impressed, 

 the anterior narrow, elongated, the posterior oval or roundish. Pallial 

 line somewhat irregular, the pallial sinus moderately deep, broadly 

 triangular. 



Length, 73 mm. ; height, 52 rum. ; diameter, 29 mm. (type). 

 Length, 102 mm. ; height, 60 mm. ; diameter, 37 mm. 



Type in the Mus. Hist. Nat., Paris. 



Hob. North and South Islands, and Chatham Islands ; from low- 

 water mark to about 5 fathoms, burrowing 12 in. to 18 in. deep in 

 sand. 



Remark. P. Solandri was found at Tauranga by Dieffenbach ; 

 it is a more compressed form. 



Fossil. Miocene and Pliocene. 



