i S 6 DISCOVERY REPORTS 



THE MOLLUSCAN FAUNA OF NORTHERN 



NEW ZEALAND 



A noteworthy feature of the fauna from these islands and the far north of the North 

 Island generally, is the number of genera and species typical of Australian seas. To the 

 known list of these occurrences may now be added the following genera : Cratis, Dimya, 

 Epicodakia, Bor?iiola, Zeidora, Starkeyna, Coenaculum and Pedicidaria. 



In 1925, Finlay (Verbeek Mem. Birthday Vol., p. 168) published a manuscript scheme 

 of Iredale's, dividing the New Zealand faunal subregion into the following five 

 provinces : 



Kermadec Province = Kermadec Islands. 

 Cookian Province = North Island of New Zealand. 

 Forsterian Province = South and Stewart Islands. 

 Moriorian Province = Chatham Islands. 

 Rossian Province = Subantarctic Islands, including 



Macquarie Island. 



In a later paper 1926 (Trans. N.Z. Inst., lvii, p. 328) Finlay added the proviso that 

 " the Cookian and Forsterian provinces as defined may not be natural and may be sub- 

 divisible later — in which case the present names are to be retained for the southern 

 portions of each island. Cook Strait has been adopted as a temporary dividing line 

 purely for present convenience ; many characteristic regional forms are known to range 

 across it. The quite recent development of Cook Strait as a geomorphic feature may 

 account for this. . . . North of the Hauraki Gulf there may possibly be a different 

 provincial region (the Cape Maria van Diemen fauna seems notably distinct)." 



Finlay 's suggested new province for the Cape Maria van Diemen area is undoubtedly 

 a good one, and since the material herein described contains additional evidence of the 

 distinctive character of its fauna I have no hesitation in accepting this area as a dis- 

 tinctive province and provide for it the name Aupourian. It includes the northernmost 

 portion of Finlay 's Cookian Province and in extent covers the Three Kings Islands and 

 all that part of the North Auckland Peninsula above Ahipara on the west and Whangaroa 

 on the east coast. It also seems to me that the Cookian should comprise all the rest of 

 the North Island and the northern part of the South Island down to Westport on the 

 west coast and Bank's Peninsula on the east. Below this on both coasts extensive shingle 

 beaches sparse in marine fauna form a good boundary, a "no-man's-land" as it were, 

 between the Cookian and the rock-bound Otago area plus Stewart Island, which is 

 another quite compact and well-defined faunal province (Finlay 's Forsterian, in part). 



Among the distinctive marine molluscs of the Aupourian are the following : Gomphina 

 maorum, Smith; Zegalerns tiimens, Finlay; Venericardia reinga, Powell; Herpetopoma 

 mariae, Finlay; Notocochlis migratoria, Powell; Cosa laevicostata , Powell; Galfridus 

 virginalis, Suter; Marginella vailei, Powell; and a large number of species described 



