LIST OF MOLLUSCA COLLECTED 163 



Family RETUSIDAE 

 Retusa cookiana (Suter, 1909). St. 933. Retusa aupouria, n.sp. St. 933. 



Family SCAPHANDRIDAE 

 Cylichnina thetidis (Hedley, 1903). St. 933. 



Amphineura 



Family LEPIDOPLEURIDAE 

 *Parachiton textilis, n.sp. St. 934. 



Family CRYPTOCONCHIDAE 

 Notoplax aupouria, n.sp. St. 934. Notoplax websteri, n.sp. St. 934. 



The collection thus contains 234 species of which 128 have not hitherto been 

 described. There are six new genera, and thirteen which have not previously been 

 reported from New Zealand waters. In the systematic account which follows descriptions 

 are given of two additional new species from other sources. 



SYSTEMATIC ACCOUNT 

 Class PELECYPODA 



Family NUCULIDAE 



Genus Pronucula, Hedley, 1902 



Type (original designation) : Pronucula decorosa, Hedley 



Pronucula maoria, n.sp. (Plate XLV, fig. 8). 



Shell minute, ovate-rhomboidal, inflated, very thin, fragile. The only sculpture, 

 apart from regular spaced concentric growth lines, is in the form of subobsolete delicate 

 dense radial striae, which are only just visible on the exterior near to the ventral margin, 

 but form a crowded weak crenulation on the inner edge of the valve. Beaks bluntly 

 rounded, set at about the posterior fourth. Hinge plate arched, extremities separated 

 by a broad triangular chondrophore, anterior side with five squarish teeth, posterior 

 side with three. Colour dull silvery white. 



Length i-8 mm.; height 1-5 mm.; thickness (one valve) 0-55 mm. (Holotype). 



Habitat: Off Three Kings Islands, St. 933, 260 m. 



Two other recent species are known from the New Zealand region : P. mesembrina, 

 Hedley, 191 6, from 60 fathoms off Macquarie Island, and P. tenuis, Powell, 1927, from 

 100 fathoms off Puysegur Point, south-west Otago. 



