SUTEE : NEW ZEALAND SPECIES OF CEIOXE. 203 



probable, that in the collection used for study, only one of the species 

 is represented, and this may be very variable, as is the case with 

 C. )nesodesma, and so one easily comes to the conclusion that the 

 different species have been established on extreme forms which should 

 be considered as one species only. 



Besides this, New Zealand conchologists are greatly handicapped in 

 their work by the want of the necessary literature and type-specimens 

 for comparison. For a number of years I have tried to get specimens 

 from various localities in New Zealand, and to a certain extent have 

 been successful. I have thus been enabled to study carefully these 

 nearly allied forms of Chione, and I now venture to publish the result 

 of my investigations. 



Chione crassa (Quoy & Gaimard). 



Venus crassa, Q. & G. : Yoy, Astrolabe, Zool., vol. iii (1834), p. 525, 



pi. Ixxxiv, figs. 7-8. 

 Venus crassa, Gray : in Dieffenbach's Travels in N. Zeal., vol. ii 



(1843). p. 250. 

 Chione gihbosa, Hutton : Cat. Mar. Moll. N. Zeal., 1873, p. 71; 



Journ. de Conch., vol. xxvi (1878), p. 49; Man. N. Zeal. Moll., 



1880, p. 148. 

 Venus gihhosa, Hutton : Macleay Memor. Yol., Linn. Soc. N.S. Wales, 



1893, p. 81, pi. ix, fig. 88. 

 Chione gihhosa, Suter : Trans. N. Zeal. Inst., vol. xxxiv (1902), 



p. 222. 

 Shell globose, orbicular, subequilateral, very thick, umbones hooked, 

 heart - shaped, lunule large and well marked, escutcheon deep. 

 Yalves concentrically striated, the costse partly united and forming 

 bundles of ribs. Colour whitish or yellowish, with two light-reddish 

 bands converging towards the umbo ; this number is fairly constant. 

 Interior white, bordered by dark violet. The muscular impressions 

 have pale-reddish striations ; the margin is denticulated the whole 

 length, the ventral margin slightly inflexed posteriorly. The three 

 cardinal teeth are strong. Length 27, height 24*75, diam. 18 mm. 

 (Q. & G.). 



The lunule is veiy distinct, rather large, heart-shaped. 

 I have specimens fi'om Preservation Inlet and Stewart Island. 

 One of the latter has exactly the measurements given above, the 

 others are smaller. The concentric ribs are separated by naiTow, 

 deep grooves ; they are slightly convex, with a sharp edge above. 

 The pallial sinus is short, regularly triangular, pointing to the 

 anterior adductor muscle. 



Chione gihhosa was founded on a single right valve only. In the 

 "Revision of the Recent Lamellibranchiata " Hutton omitted the 

 species as "found fossil only." The Pliocene specimens I possess are 

 less gibbous and smaller, but so is also the recent specimen I have 

 from Preservation Inlet. The fossil specimens agree with the 

 diagnosis and figures of V. crassa, Q,. & G., fairly well, and Button's 

 name therefore becomes a synonym. 

 C. crassa is a rather rare species now. 



