SUTER : NEW ZEALAND SPECIES OF CHIONE. 



205 



I cannot consider this more than a subspecies. It differs from the 

 species chiefly in its colour and markings, and especially lu the 

 cordate, short lunule, which is much more like that of crassa. 



Chione stjbsdlcata, n.sp. 

 Venus sulcata, Hutton: Proc. Linn. Soc. N.S. Wales (2), vol. i (1887), 



p. 226 (Wanganui System). 

 Vtnus sulcata, Hutton: Pliocene Moll, of N. Zeal., p. 81, pi. ix, 

 fig. 87, in Macleay Memorial Vol., 1893. 

 Some months back, when arranging the New Zealand shells in the 

 Colonial Museum, Wellington, I came across some recent valves of a 

 Chione I had never seen before. They were collected by the late 

 Mr. Traill near Stewart Island. I soon found out, however, that 

 they are closely allied to Button's Venus sulcata} In the Macleay 

 Memorial Vol. Capt. Hutton seems to be rather doubtful whether the 

 Pliocene form is identical with the Miocene. I have not seen Miocene 

 specimens, but I have good examples from the Pliocene of Wanganui 

 and Waikopiro, and these, as well as the recent specimens, show 

 a character which was not mentioned by Capt. Hutton ; they are all 

 finely and closely radiately striated, the striae running over the broad 

 concentric ribs. This radiate striation is visible in some specimens to 

 the naked eye, in others it can only be seen by the aid of a good lens. 

 1 have asked Professor W. B. Benham, curator of the Otago Museum, 

 to kindly examine the type-specimen, which is from the Miocene of 

 Napier, with regard to this radiate striation, and he informs me 

 "that 'the concentric ridges are perfectly smooth; there are no 

 striations visible even with a hand lens." Therefore the Pliocene and 

 recent forms may be considered a distinct species, and require a new 

 specific name. . -• j 



The specimens I have seen show some variation in the proportion ot 

 the height to the length, viz. : — 



The Pliocene type, according to Hutton, is 35 x 41mm., ratio 1 : 1-17 



My Pliocene specimen from Waikopiro is 31 x 36 ,, ,, 1 : 1'16 



One recent valve from Stewart Island is 34x41 „ " : ' ',. 



Another „ „ 41 x 47 „ „ 1 : 1-1& 



The lunule in Pliocene and recent specimens is oblong cordate, 



striated, and well defined; the escutcheon long and narrow. The 



pallial sinus is short, pointing to the middle of the anterior adductor 



muscle. The margins of the valves are finely crenulated. 



This is another example of one of our Pliocene molluscs having its 

 existence down to the present time. 



Type.— Venus sulcata, Hutton, of the Pliocene (1887), nee 

 V. sulcata, Hutton, 1875. 



1 Trans. N. Zeal. Inst., vol. vii (1875), p. 458, pi. xxi. 



