Sea Shells 
of New Zealand 
Plate II 
No. 4 
smaller ribs in the interspaces, all crossed by concentric 
growth lines. The colour is universally dark bluish grey, 
the ribs being of a darker shade. The markings, however, 
show considerable variation and are often handsome, some- 
times black bifurcating broad streaks on a creamy ground. 
The apex is at the anterior third or fourth. The interior 
is silvery, showing the external colour markings, of course 
in thin shells only; the central area is brown or olive 
green. Margin somewhat crenulated in outline—that is to 
say, notched or wavy ered minor degree. The markings, 
being so varied, have given rise to a subdivision of this 
species into seven sub-species. Since this classification was 
announced further research has recently resulted in four of 
these varieties being discarded, one so-called sub-species 
being only met with in Australian waters, while the other 
three are so ill defined that it is impossible to isolate them 
as separate varieties. Some of Hutton’s remarks, appended 
to his descriptions of the limpets—such as, “probably a 
small variety of the last...” “this species passes into the 
next,” ... “perhaps a variety of the last’’—give one some 
idea of the perplexing modifications presented by the 
patellae, even to scientific observers. How, then, shall the 
amateur decide? His simplest plan is to obtain typical 
specimens of the varieties hereafter described, label them 
and keep them apart; then to make a large collection of all 
the other limpet species, noting their peculiarities, where 
they differ from each other, and, above all, how they co- 
incide. A tray of fifty Helcioniscus radians, carefully 
spaced and displayed, make a delightful collection, and 
should comprise all ages and sizes, shapes and colour 
markings. 
The typical shell is about an inch and three-quarters 
long, by an inch and a quarter wide. It is a common 
species, and is found throughout New Zealand. Mount 
Maunganui. 
HELCIONISCUS RADIANS var. ARGENTEUS— 
(helcion, a breast collar; radians, having rays; argenteus, 
silvery ).—This variety or subspecies is named from its 
silvery interior. Outside it is similar to the species in 
having twenty to twenty-five ribs, interspersed with smaller 
ones. The central area is “greyish white or cream colour, 
rusty in old specimens.” (Suter). The shell is said to be 
more elevated than in the species, but this is not always so; 
the reason why some of the limpets are highly conical while 
others of the same species are more depressed or flattened 
may be readily accounted for by noting the nature of the 
tock upon which they are found. If from the rugged 
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