2 2o DISCOVERY REPORTS 



crowded delicately granulate fine closely spaced longitudinal lirae which curve inward 

 slightly at the dorsal ridge, a few short lirae being intercalated above to fill the space 

 occasioned by this slight crowding. There are about ioo of the longitudinal lirae across 

 the whole of a valve, those towards the sides becoming oblique. Posterior valve large 

 and long, almost as long as wide ; mucro very close to the lower margin ; ante-mucronal 

 area extremely large, triangular, rounded, low-arched and sculptured similarly to the 

 central areas of the median valve, longitudinal lirae totalling about seventy across the 

 valve. Post-mucronal area radially quincuncially lirate. Insertion plates absent, sutural 

 laminae small. Colour uniformly pale buff. 



Length 2-5 mm.; breadth 7-5 mm.; height 3-5 mm. median valve (Paratype). 



Length 2-5 mm.; breadth 3-8 mm.; height 1-3 mm. posterior valve (Holotype). 



Habitat: Off Three Kings Islands, St. 934, 92 m. 



This is the second New Zealand Parachiton to be described, the other (P. subant- 

 arcticus, Iredale and Hull, 1930, Aust. Z00L, vi, pt. 2, p. 157) being from 95 fathoms off 

 the Auckland Islands. The Auckland Island species is based on a single median valve 

 which differs from that of the Three Kings Islands shell in having the longitudinal 

 sculpture coarser and in the form of chains of pustules. Iredale and Hull (1929, he. cit., 

 pt. 1, p. 30) state that an undescribed species of Parachiton was dredged off the north of 

 New Zealand by Scott's Antarctic Expedition. 



Although no complete examples of the above new species are available there are suf- 

 ficient valves to furnish an adequate description of the species. 



Family CRYPTOCONCHIDAE 

 Genus Notoplax, H. Adams, 1861 

 Type (by monotypy) : Cryptoplax (Notoplax) speciosa, H. Adams 

 Notoplax aupouria, n.sp. (Plate XLVIII, fig. 1). 



Median valves very narrow, tegmentum triangular, higher than broad. Sutural 

 laminae wide, sinus narrow, slits one on each side, weak. Dorsal area smooth, narrow, 

 sharply raised, sides almost parallel throughout. Sculpture of prominent raised oval 

 pustules arranged in eleven vertical rows on each lateral area. A weak diagonal fold 

 traverses the lower part of the valve, commencing at the umbo and terminating at the 

 sutural slits. Colour of tegmentum pinkish buff, sutural lamellae white. 



Length (tegmentum) 3-6 mm.; breadth (tegmentum) 3-5 mm.; maximum breadth 

 5-3 mm.; height 2-5 mm. (Holotype, one median valve). 



Habitat: Off Three Kings Islands, St. 934, 92 m. 



This is a very distinctive species, most nearly allied to the Southern Australian- 

 Tasmanian speciosa, the genotype. No complete examples were taken. 



Notoplax websteri, n.sp. (Plate XLVIII, figs. 2, 3). 



Median valves rather broad, tegmentum much broader than high. Sutural laminae 

 not very wide, sinus broad. Dorsal area broadly wedge-shaped and strongly beaked. 



