288 



There se-ems to be a tendency in both these species to 

 develop special racial characteristics, but these features do not 

 appear as yet to be fixed. 



Thus in New South Wales specimens of A . granostriatus 

 the lanceolate character of the pustulose sculpture is exception- 

 ally developed. It appears on close inspection that the 

 shallow flat pustules are built on the erown of slight radial 

 undulations, hardly ribs, and the shallow pustules merge into 

 this undulation, giving a lanceolate character to the pustules 

 very distinct from the normal, obovate, well-raised pustules 

 of hednalli. 



Then, again, in Tasmania we have collected by Mr. W. 

 L. May, in Ralph Bay, a divergent form of hednalli, and I 

 note a specimen kindred thereto from Frederick Henry Bay, 

 in the same State. 



I collected on March 27, 1920, at the latter locality, one 

 specimen that seems quite typically A. granostriatus, and 

 several that correspond with A. hednalli, with deep longi- 

 tudinal grooving between granulose ribs, in the dorsal area. 

 But my comments on the Ralph Bay specimens, lent me by 

 Mr. May, are as follows : — In these specimens the dorsal area 

 is almost smooth, as in granostriatus, but the longitudinal 

 grooving exists to a limited extent in some of the valves in 

 each; the girdles are but slightly spiculose and quite typical 

 of hednalli. 



The pustules are chiefly obovate, the shells are large, and 

 in all the pustules are strongly raised, characters that see^m 

 persistent in hednalli in spite of other variations. I think 

 we are justified in assigning this variety to hednalli, but a 

 more complete investigation of material collected from widely- 

 separated localities may reveal further differences. 



In my 1918 Distribution List I referred to a specimen of 

 A. zealandiciis, Quoy and Gaimard, which is in my collection. 

 This was given to me by Dr. H. Leighton Kesteven, of Sydney. 

 I have since got into touch with him, and he tells me that it 

 was taken in Port Jackson, New South Wales. So I now 

 add this species to the Australian fauna. 



A comparison of this shell with those from New Zealand, 

 as well as with A. hednalli, reveals some very interesting 

 features, some of which show a distinct relationship between 

 this species and hednalli. 



But on comparing the shells given me as A . zealandicu^, 

 by the late Mr. Suter, from Auckland Harbour, with those 

 given me recently by Mr. A. E. Brookes, from Doubtless Bay, 

 reveals the fact that there are considerable differences. 



Those from Auckland Harbour have narrow, longitud- 

 inally-grooved dorsal areas, whereas those from Doubtless Bay 



