Modiolarca.] PELECYPODA. 895 



Hinge : Right valve with 1 or '2 small teeth, which sometimes are 

 obsolete ; left valve usually with 1 small tooth only ; all the teeth 

 are roundish, and situated below the umbo. Ligament subinternal, 

 rather long, narrow. Adductor-scars distinct. 



Dimensions of largest valve : Length, 4-2 mm. ; height, 3 mm. ; 

 diameter, 1 mm. 



Type in my collection. 



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



Remarks. In contour the species approaches M. bicolor, von 

 Martens, and M. kerguelensis, E. A. Smith ; both, however, are much 

 larger shells, and certainly distinct. 



2. Modiolarca pusilla, Gould, 1850. Plate 52, fig. 6. 



Mi/tiht* (Modiolarca) pusittus, Gould. P. Bust. S.X.H., iii, 1850, 345 ; U.S. 

 Expl. Exp., xii, 455, atla* f. .")S.">. Ma.lmini,-,! /,ii<i//n, Gould: E. A. 

 Smith, Phil. Trans. Roy. Soc., clxviii, 1879, 191; P. Mai. S., iii, 24; 

 Index, 94 ; Ireclalc, T. N.Z.I., xl, 38f>. 



Si/ ell minute, thick and solid, transversely oval, inflated, subcylin- 

 drical. Beaks nearly terminal, elevated and tumid, somewhat ex- 

 curved. Dorsal and basal margins nearly parallel ; anterior end verti- 

 cal, the basal angle obtuse : posterior end broadly rounded. Sculpture 

 consisting of concentric growth-lines. Epidermis very delicate. Colour 

 pale cinereous, sometimes tinted reddish. Interior clouded brown, and 

 an intense red-brown : hinge-margin intense blood-red. Hinge with a 

 single tooth in each valve, sometimes bifid. Ligament short. 



Length. 5 mm. ; height, 3-25 mm. (type). 



Type in the U.S. Nat. Museum, Washington. 



Hob. Cape Saunders (Iredale) ; Antipodes Island (Captain Hut- 

 ton) ; Campbell Island (Filho!) ; Macquarie Island (A. Hamilton). 

 The type is from Tierra del Fiiego. 



3. Modiolarca Smithi, n.n. Plate 52, fig. 7. 



Modiolarca bicolor, E. A. Smith, P. Mai. S., iii, 1898, 25, f. 3 in text : not of 

 von Martens, 1885. 



Shell minute, inequilateral, oblong, rather compressed laterally, 

 white and reddish-brown. Beaks but little produced, in front of the 

 middle, rounded. Anterior end shorter, narrowed, rounded, basal 

 margin lightly convex ; posterior end broader, convex, the dorsal 

 margin straight or lightly curved. Sculpture consisting of fine dense 

 concentric striae. Epidermis thin, shining. Colour : Anterior and 

 basal part of the valves white, umbones and posterior portion reddish- 

 brown. Interior shining, white in front, reddish behind. Margins 

 smooth, sharp. Hinge with 1 tooth in the left, 2 in the right valve. 

 Ligament subinternal, small, oblique. Adductor scars fairly large ; be- 

 hind the anterior scar and under the umbo the valves are strengthened 

 by a white callus. 



Length, 3-5 mm. ; height, 2 mm. ; diameter, 1-5 mm. 



Type in the British Museum : co-type in my collection. 



