156 LASEID&. 
lamellae distant, regular, the interstices decussated with elevated radiat- 
ing strize, and transverse lines; umbones nearly median, rather prominent ; 
anterior side rounded, sub-truncate, and sub-angulated ; posterior side 
rounded ; anterior cardinal tooth broad and prominent ; interior thicken- 
ed white, ventral margin crenulated (Adams). 
Australia and New Zealand. (Strange). 
Genus, DIPLODONTA—Bronn. 
Mantle-margins nearly plain ; pedal and anal apertures wide apart. 
Shell equivalve ; two unequal cardinal teeth in each valve ; the anterior 
of the left and the posterior of the right bifid ; ligament external. 
D. zealandica, Gray, Dief:., N.Z., i., p. 256; Smith, Voy. Erebus 
and Lerrors pl. sapere 3) LE. tncullta, “Gould, OS... Lx. Lop) xi pe An yas 
Atlas, f. 524. Shell sub-orbicular, rather compressed, rather solid, opaque 
white, smooth, very slightly concentrically striated, and covered with a 
thin smooth periostraca (Gray). Rather compressed, smooth, very 
slightly concentrically striated, rather solid ; opaque white. 
Height, °75 ; length, °75. 
Auckland. 
D. globularis, Zamark, Zc, vi, p. 2313 Reeve, Conch. Ic. (Lu- 
cina,) f. 53. Orbicular, inflated, umbones rather prominent ; very finely 
concentrically striated, thin, pellucid ; horny white. 
HHeight,1 ; length, 1°12. 
Auckland to Stewart Island, 14 fathoms. Australia. 
D. striata, Mutton, Jour. de Conch., 1878, p. 51 ; L. nove-zealandia, 
Reeve, Conch. Lc. (Lucina,) pl. ix., f. 14 (not of Gray.) Shell somewhat 
globose, inequilateral, swollen posteriorly, concentrically rudely, irregu- 
lary striated ; no lunule ; hinge with two central teeth in each valve, one 
of which is erect and bifid ; whitish, covered with a light brown epider- 
mis (Reeve). 
Height, -4; length, °4. 
New Zealand. (Cuming). Kapiti, Cook Strait. 
FAMILY—LASEID. 
Mantle with only one siphonal opening, the anal, which is sometimes 
sessile, sometimes produced into a tube ; the mantle folded anteriorly 
into a canal or tube. Foot ligulate, grooved, with a byssiferous organ, 
and capable of being used as a creeping disk. Shell thin, often trans- 
parent, and sometimes gaping. Hinge. straight, with one or two 
cardinal teeth ; lateral teeth compressed or none. 
Genus, KELLIA—Turton. 
A very short posterior. anal siphon ; anterior tube undivided, entire ' 
below. Shell sub-orbicular, sub-equilateral, closed, smooth or concen- 
trically striated ; one valve with two cardinal teeth near together and a 
