Modiolus.] PELEC'YPODA. 867 



Diameter Ant. -post., 25 mm. ; dorso-ventral, 12 mm. : thickness, 

 13 mm. A large specimen from the Auckland Islands measures 49 mm. 

 by 20 mm. by 23 mm. 



Type in the K.K. Hofmuseum, Vienna. 



Hab. Throughout New Zealand. Auckland Islands. 



2. Modiolus australis, Gray, 1827. Plate 58, fig. 5. 



Modiola australis, Gray, App. to King's Voyage, ii, 1827, 477 ; Hanley, 

 Cat. Rec. Biv. Shells, 235 ; Conch. Icon., x, pi. 5, f. 21 ; M.N.Z.M., 168 ; 

 Pritchard and Gatliff, P.R.S. Vic., xvii (n.s.), 251. Perna auslralis, 

 Gray : Angas, P.Z.S., 1865, 653. Volsella australis, Gray, Index, 94. 

 Mytilus (Modiola) areolatus, Gould, P. Bost. S.N.H., iii, 1850, 343 ; U.S. 

 Expl. Exp., xii, 452, atlas f. 562. 



Shell moderately large, rather solid, transversely ovate, hirsute, 

 brown, with a rather large ventral byssal fissure. Beaks very near 

 the anterior end, somewhat distant, tumid, obtusely angular. Anterior 

 end swollen, much narrowed, narrowly convex, the dorsal margin 

 rectilinear, ascending, gradually curving at about half its length. 

 Posterior end compressed, broadly rounded, the ventral margin concave 

 near the beaks ; a constriction running from the posterior end of the 

 byssal fissure to the beaks marks off a triangular segment of darker 

 colour. Sculpture consisting of fine concentric growth-lines, crossed 

 by very fine radial striae ; triangular segment with numerous short, 

 arrow-headed, radiating undulations. Epidermis coriaceous, shining, 

 produced into long beard-like fringes on the posterior half of the 

 shell. Colour chestnut-brown, paler along the umbonal ridge. Interior 

 cream-colour, livid around the ligament, the dorsal portion flesh- 

 coloured. Margins smooth, sharp. Hinge-line very narrow, smooth. 

 Ligament fairly long, mostly internal. Adductor-scars but faintly 

 impressed. Pallial line simple. 



Diameter Ant. -post., 44 mm. ; dorso-ventral, 26 mm. : thickness, 

 20 mm. A large specimen from Stewart Island measures 108 mm. by 

 60 mm by 45 mm. 



Type in the British Museum. 



Hab. Throughout New Zealand. Chatham, Auckland, and Camp- 

 bell Islands. Also Tasmania and Australia. 



Maori. Purewha. 



Fossil in the Miocene and Pliocene, 



3. Modiolus fluviatilis, Hutton, 1878. Plate 58, fig. 6. 



Modiola securis, Lamarck : Hutton, C.M.M., 78 ; not of Lamarck. M. fluvi- 

 atilis, Hutton, J. de Conch., 1878, 53 ; M.N.Z.M., 168 ; P.L.S. N.S.W., 

 ix, 530. Volsella fluviatilis, Hutton, Index, 04. 



Shell small, transversely ovate, inflated, with a blunt umbonal 

 carina, concentrically ridged, black. Beaks near the anterior end, 

 but farther back than in M. ater, fairly close together, tumid, carinated, 

 the carina extending to the posterior end of the basal margin. Anterior 

 end narrowed, swollen, narrowly rounded, the dorsal margin ascending, 



28* 



