1294 niPi.ODON 



tooth is quite rudimentary, the upper lateral tooth is a little 

 higher and more rup^ose posteriorly than the other. Interior 

 bluish-white, pearly, a little blotched with olive in the umbonal 

 cavity, where there are rather large and deep dorsal scars. The 

 adductor muscle scars are shallow. The young specimens are 

 slightly winged. 



Length 45, height 24, diam. 8 mm.'' (Suter). 



Type locality. Lake Manapouri, New Zealand. 

 Diplodon mcnsirsi subsp. lucasi Sutrr, Trans. X. Z. Inst.. 



XXXVIT, 1904, p. 239, figs. 2, 3. 



"This subspecies is nearest to the typical aiicklandica, but 

 is distinguished from it by its exceptionally compressed form, 

 the thinness of the shell, the strongly marked and close, con- 

 centric lines, the more tapering posterior margin, and the 

 feebly developed pseudocardinals. The radiate, nodulous sculp- 

 ture is found in manv specimens of menzicsi and its sub- 

 species." 



Diplodon waikarensis (Colenso). 



.\n unfigured species having the posterior slope keeled, 

 shaq), the primary tooth large and much crested. It is a large 

 form having a length of 88 millimeters and a height of 57. 

 .According to Suter it lives in quiet, pure water and he believes 

 it to be a variety of D. mensiezi. I am inclined to think it 

 distinct on account of the keeled posterior slope. The descrip- 

 tion of this species is inaccessible to me at present. 



Suter (1. c), says that Colenso's diagnosis is incorrect, and 

 that the shell is not keeled. He considers it a synonym of 

 metime."i. 



Waikare Lake, X'ew Zealand. 

 Unio waikarensis Colenso, Tasm. Jl. X^ Sci., II, 1845, p. 250, 



footnote. 

 Diplodon waikarensis Simpson, Svn., 1900, p. 890. — Sltter, 



Trans. N. Z. Inst., XXXVIT, 1904, p. 235. 



Diplodon zelebort (Dunker). 



Shell long rhomboid, rather solid, convex or subcompressed, 

 inequilateral : beaks small, sharp, with subnodulous, curved, 

 subradial ridges ; posterior ridge narrowly rounded above, 



