896 PELECYPODA. [Eulumellibranchia. 



Hob. Macquarie Island (A. Hamilton). 



Remark. -- Distinguished from M. pusilla, Gould, and M. minuta. 

 Dall, by its very different form, the anterior end being conspicuouslv 

 produced and narrowed. (E. A. Smith.) 



4. Modiolarca tasmanica, Beddome. 1881. Plate 52, figs. 8. a. 



Modiolarca tasmanica, Beddome, P.R.8. Tas., 1880 (1881), 168; Tate and 

 May, P.L.S. N.S.W.. xxvi, 4:5!). f. 12 in text ; Vereo, T.R.S. S.Aust., 

 xxxi, 105. 



Shell small, inequilateral, oval, rostrate in front, ventricose, smooth, 

 reddish-brown. Beaks anterior, not much produced, rounded. Anterior 

 end obliquely produced, forming an angle with the basal margin, 

 which is distinctly sinuated in front, thus forming a conspicuous 

 short rostrum ; posterior end somewhat produced, regularly convex, 

 the dorsal margin lightly arcuate. Sculpture consisting of very fine 

 and close concentric stria3. Epidermis thin, slightly polished. Colour 

 pinkish to reddish-brown, the anterior part usually whitish. Interior 

 of the same colour, smooth. Margins smooth, sharp. Hinge with 2 

 small teeth ; hinge-plate with 2 small pits anteriorly. Ligament 

 narrow, subinternal. Adductor-scars fairly large, distinct. 



Length, 5 mm. ; height, 3 mm. ; diameter, 2-8 mm. 



Hob. Near the Bounty Islands, in 50 fathoms (Captain Bollons). 

 Also Tasmania, South Australia, and Victoria. 



5. Modiolarca trapezina, Lamarck, 1836. Plate 63, fig. 6. 



Modiola trapesina, Lamarck, A.s.V., ed. 2, vii, 1836, 24. Modiolarca tra- 

 pezina, Lam., Conch. Cab., viii, pi. 6, f. 16, 17 ; Hanlev, Cat. Rec. Biv. 

 Shells, 237 ; Gray, Synopsis Brit. Mus., 1840, 151 ; P.Z.S., 1847, 199 ; 

 Ad. G.R.M., iii, pi. 122, f. 1 ; Chenu, Man. Conch., ii, 156, f. 777 ; E. A. 

 Smith, Chall. Rep., xiii, 27!! ; Martens and Pt'effer, Moll, von Sud- 

 Georgien, 127, pi. 4, f. 13 ; Pelseneer, Voy. " Belgica," 11. Phaseolicama 

 trapezina, Lam. : Hupe, in Gay's Hist. Chile, Malacologia, pi. 8, f. 9. 

 P. magdlanica, Rousseau, Voy. P.S., 116, pi. 26, f. 2. Gaimardia tra- 

 pesina (Lam.), Gould, U.S. Expl. Exp., xii, 459, atlas f. 568. Modiolarca 

 trapezina, Lam., E- A. Smith, P. Mai. S., ii, 24 ; Index, 94. 



Shell small, ovate-trapezoidal, thin and fragile, ventricose. Beaks 

 near the anterior end, prominent, prosogyrate, contiguous. Anterior 

 end compressed, sloping abruptly to the base, dorsal margin nearly 

 rectilinear ; posterior margin regularly rounded ; ventral margin 

 somewhat sinuous and gaping anteriorly, forming a small elliptical 

 passage for the foot and byssus. Sculpture consisting of concentric 

 growth-lines. Epidermis thin, shining. Colour usually pale olive, 

 I >ut occasionally bright yellow, orange, dark brown, and almost black. 

 Interior always deep purple within the pallial impression, and rosy- 

 white outside of it. Hinge : Right valve with 2 small oblique cardinal 

 teeth, which receive 2 corresponding ones of the opposite valve ; these 

 teeth are frequently inconspicuous. Ligament narrow, short, partly 

 internal. Adductor-scars quite distinct, the anterior surrounded by 

 white callus. 



Length, 17 mm. ; height, 13 mm. ; diameter, 8-5 mm. 



