Marshall. — Tertiary Molluscan Fauna of Pakaur'angi Point. 271 



Sarepta aucklandica n. sp. (Plate XIX, figs. 5, 6.) 



Shell small and thin : height, 9 mm. ; length, 6 mm. Shape semi- 

 orbieular. Umbo fairly prominent, almost in the middle of the dorsal 

 margin. Ventral margin circular. Dorsal margin descending slowly behind 

 but gently rounded in front. Surface of the shell smooth and almost 

 polished, though faint concentric lines can be distinguished. About 9 small 

 teeth can be distinguished on either side of the umbo, but they commence 

 rather more closely to it on the posterior than on the anterior side. 

 Ligament-pit triangular and directed forward. 



Not verv common. Only two good valves (both left) were found. 



1 am indebted to Mr. Suter for information as to the correct place of 

 this species in classification. Type in the Wanganui Museum. 



Mytilus torquatus n. sp. (Plate XXI, figs. 3, 3a.) 



Shell small, elongated, inflated : height, 22 mm. ; length, 14 mm. ; thick- 

 ness, 9 mm. Inflated anteriorly, compressed posteriorly. Slightly winged 

 about the middle. Beak acute, strongly curved anteriorly. Dorsal margin 

 ascending for a short distance, then bent quickly through an angle of 70°, 

 forming a straight line along the anterior margin. Ventral margin gradually 

 rounded, returning with a gradual sweep to the dorsal margin. Surface 

 finely striated. The striae ramify repeatedly along the central line, then 

 extend without further branching to the margin. Striae rounded, very fine 

 on the anterior slope, about as wide as the interstices. They are crossed 

 by very wide concentric undulations and by small cross-threads. 



Two specimens only, both right valves, in good condition. Closely 

 related to M. huttoni Cossmann = M . striatus Hutton. 



Spondylus aucklandicus n. sp. (Plate XXI, figs. 2, 2a.) 



Shell of moderate size, only 20 mm. high and 30 mm. long. Strongly 

 inequilateral with a considerable posterior expansion. Hinge-line straight 

 with a typical provinculum. On the left valve the area is small and 

 almost linear. Umbo not prominent. Crural teeth very large and with 



2 or 3 crenulations on the dorsal side. Ligament-pit distinct, with a well- 

 marked ridge on either side. Ornamentation : One or two broad concentric 

 undulations crossed by a number of scaly but not spiny radiating ridges of 

 extremely unequal size. Generally 3 or 4 smaller ribs between the larger 

 ones. The ribs are somewhat irregularly curved, and are continued to 

 the margin, near which they are discernible also on the inner side. On the 

 inner surface, however, they only extend as far as the pallia! line. 



Two specimens only, one of which is in a very good state of preservation . 

 Type in the Wanganui Museum. 



No species of this genus has previously been recorded from the 

 Tertiary deposits of New Zealand, but Professor Woods has lately recorded 

 a specimen, too imperfect for description, from the Cretaceous rocks of North 

 Canterbury. There is also a very large specimen of Spondylus in the 

 Auckland Museum which is labelled as coming from Hawke s Bay. 



Dosinia tumida n. sp. (Plate XXI, figs. 4, 4a.) 



Shell small, ovato-orbicular : height, 17 mm. ; length, 20 mm. ; thick- 

 ness, 7 mm. Dorsal margin sloping gently posteriorly and developing 

 gradually into the almost circular curve of the ventral margin. Inner 

 surface of the margin delicately crenulated. Umbo fairly prominent and 

 distinctly bent anteriorly. Sculpture a fine concentric striation with 

 strongly incised concentric grooves at intervals. Hinge-plate rather small. 



