Mi/llita.] PELECYPODA. 929 



1. Myllita Stowei, Hutton, 1873. Plate 54, fig. 2. 



l j !lthina Stowei, Hutton, C.M.M.. 7<> : J. de Conch., xxvi, 51 ; M.N.Z.M.. 

 157: P.L.S. N.S.W., ix. r>2(i : K. A. Smith. A.M.N.H. (6), viii, 1891. 

 230, pi. 13, f. D-F. 



Shell small, transversely oval, thin, whitish, equilateral, divari- 

 cately ribbed. Beaks prominent, convex, roundly pointed, contiguous. 

 Anterior end rounded, subangled above on meeting the nearly hori- 

 zontal dorsal margin ; posterior end similar to the anterior, but the 

 dorsal margin slightly sloping, basal margin straight. Sculpture : 

 The whole surface minutely sagrinate, with sharply raised, distant, 

 divaricating riblets, the angles in a straight vertical line from the 

 apex to the base, the interstices much broader than the riblets ; 

 towards the margin a few concentric growth-lines. Colour greyish- 

 white. Interior white, polished, showing the divaricate sculpture. 

 Margins crenate. Hinge : Eight valve with a bifid cardinal just in 

 front of the umbo, 2 short anterior laterals, and 2 longer raised 

 posterior laterals ; left valve with 1 cardinal, 1 short anterior lateral, 

 and 1 longer posterior lateral tooth ; the posterior long resilifer at 

 the base of the hinge-plate usually terminating in a tubercle. 

 Adductor-scars large, subequal. Pallial line simple. 



Diameter Ant. -post., 13mm.; dorso-ventral, 7mm.: thick- 

 ness, 5 mm. (large specimen). 



Type in the Dominion Museum, Wellington 



Hab. Islet Reef, Cook Strait (type) ; Hauraki Gulf, fixed to the 

 under-side of stones by the byssus (H. S.) ; Bay of Islands (J. C. 

 Anderson) : Foveaux Strait, in 15 fathoms (A. Hamilton). 



Genus 6. PACHYKELLYA, Bernard, 1897. 



Padiykdlya, Bernard, Bull. Mus. Hist. Nat., Paris, 1897, 309. Type and 

 only species known : P. Edivardsi, Bernard. 



1. Pachykellya Edwardsi, Bernard, 1897. Plate 54, tigs. 3. a, b. 

 Pachykellya Edwardsi, Bernard, op. cit.. 309, f. 1 in text. 



Shell minute, equivalve, inequilateral, higher than long, elongated 

 anteriorly. Beaks much inclined forward, approximate, with a 

 minute globular prodissoconch. Anterior end produced below, the 

 dorsal margin descending ; posterior end much shorter, regularly 

 curved, basal margin convex. There is no umbonal cavity. Sculpture 

 consisting of very fine, sharp, and regular concentric strise. Colour 

 white, semitransparent, shining. Interior white, smooth, with a 

 straight line running obliquely from the dorsal part of the anterior 

 muscle-scar to the end of the lateral lamella opposite. Margins 

 simple. Hinge-plate interrupted in the middle by the oblique in- 

 ternal resilium ; each valve with a pair of lamellae on each side of 



30 Moll. N.Z. 



