Marshall and Murdoch. — Tertiary Mollusca. 79 



but in medium-sized examples are very distinct, and frequently the length 

 of the valve exceeds the height. 



This is the first record of a species of Miltha in New Zealand. Its large 

 size and the fact that the Lucinidae are poorly represented in this country 

 make this occurrence noteworthy. 



Miltha dosiniformis n. sp. (Plate XVII, figs. 2, 2a.) 



Shell large, solid, subrotund, somewhat compressed, the left valve rather 

 less inflated ; beaks small, a little anterior, and slightly curved forward ; 

 the anterior dorsal area narrow and inconspicuous, the margin slowly 

 declining, uniformly curved around the end and ventral margin ; the posterior 

 dorsal margin slightly convex, declining, lightly angled at its termination, 

 the end subtruncate ; the posterior dorsal area with a well-marked ridge. 

 Sculpture consists of fine concentric threads, somewhat irregularly disposed ; 

 the specimen is slightly eroded, but there does not appear to be any radial 

 sculpture. Valves united and filled with hard matrix. 



Height, 78 mm. ; length, 83 mm. ; thickness of united valves, 29 mm. 

 Another example : height, 79 mm. ; length, 81 mm. 



Type in the collection of the Geological Survey, Wellington.* 



Note. — On the card accompanying a specimen it is recorded as 

 " Dosinia sp. Age 4 to 6. Locality No. 257. Kawau Island." In 

 addition to the two complete specimens there is a large fragment with 

 the valves partly imited and showing the pallial line distant from the 

 margin ; also two smaller fragments of right valves, one of which clearly 

 shows the small deeply inflexed area in front of the beak. 



Miltha parki n. sp. (Plate XVII, fig. 3.) 



Shell large and solid, ovately subrotund, compressed, the left valve 

 more compressed than the right ; beaks prominent, curved forward, nearer 

 to the anterior end ; excavate in front of the beak with the margin sharply 

 inflexed, thence rounded, the end subangled on meeting the ventral curve ; 

 the posterior dorsal margin convex and declining somewhat sharply, the 

 end apparently slightly angled. The posterior dorsal area faintly indicated. 

 Sculpture consists of fine concentric and radiate threads of about equal 

 strength, producing minute granules. All examples have the valves united 

 and are filled with a hard matrix ; no description of the interior can therefore 

 be given. 



Height, 77 mm. ; length, 75 mm. ; thickness of the united valves, 

 25 mm. ; the diameter of the right valve about, one-third greater than 

 that of the left. Other examples : height, 70 mm. ; length, 70 mm. 

 Another : height, 64 mm. ; length, 62 mm. 



Type and co-types in the collection of the Geological Survey, Wellington. 



Locality: No. 526, Okoko-Waipa-Kawkia Road. 



The specimens were collected by Professor Park and listed as Dosinia sp. 

 {Geol. Rej)., vol. 17, p. 139, 1885). 



Note. — The three species of Miltha described may be distinguished from 

 each other by the following characters : — M . parki, by the prominence of the 

 beaks and the radial sculpture : M. neozelanica, by the anterior position 

 of the beaks and their marked forward curve ; in large specimens the 



* Fig. 2a is from the right valve of the type, prepared by Mr. J. Marwick. 



