37 



A REPLY ON THE GENERA NEPTUNEA AND SYNGERA. 

 By T. Iredale. 



Bead 9th December, 1921. 



The statement that because Murex antiquus, Linne, as C. 

 argyrostomus, was named as type of Chrysodomus, Swainson, 

 it becomes unavailable for selection as type of Neptimea, Bolten, is 

 not tenable. This particular point has been placed before the 

 Internationa] Committee on Zoological Nomenclature, and is dealt 

 with by Opinion No. 62, which has definitely decided against 

 Dr. Dall's view. As to the validity of Syncera, I quote the full 

 account, as the periodical in which it occurs is rare : " Nerita 

 Syncera H&patica, N.S. The animal of this shell differs from all 

 the others of this order, by the eyes appearing to be at the ends of the 

 tentacula ; but, I believe, that they are placed on a peduncle, as 

 long as the tentacula, and the peduncle and tentacula are sordered 

 together ". 



I leave this to malacologists to decide if such a tentative 

 statement with regard to a " new species " of " Nerita " of which 

 no conchological features whatever are given is recognizable, and 

 can be construed as anything else but a nomen nudum. 



T. Iredale, 



THE NOMINATION OF "RECENT" FOSSIL MOLLUSCA. 

 By Tom Iredale. 

 Rij,i 9th December, 1921. 



The determination of some marine mollusca from Twofold Bay, 

 New South Wales, necessitated the consideration of their fossil 

 relations, and the lack of some means of indicating the suggested 

 relationship was strongly impressed upon me. The facts concerning 

 the distribution of the recent species in connexion with the fossils 

 must first be displayed. Bass Straits differentiates two regions when 

 the littoral mollusca are regarded, but when deep-water forms are 

 examined the distinction is not so v/ell marked ; nevertheless, it is 

 present with modifications. In a given locality the deep-water forms 

 differ more or less appreciably from their littoral relatives, but in 

 two localities while the littoral shells may differ their deep-water 

 forms may be almost inseparable from each other. In other classes 

 in zoology trinomials have been utilized with success to indicate 

 geographical variation in the forms of a species. Extreme usage in 

 ornithology has tended to the confusion of representative species 

 with geographical subspecies, and in the case of marine mollusca 

 great care must be exercised lest individual be ]uistaken for 

 geographic variation. Still greater care must be taken in con- 

 nexion with deep-Avater forms, and yet more when fossils are 



