66 
THE NAUTILUS. 
NOTE ON HELCIONISCUS NIGRISQUAMATUS REEVE, SP. 
BY GEO. W. TAY'LOR. 
I have recently received from Mr. Frederick Stearns of Detroit a 
number of shells collected by himself and labelled as follows : 
“ Patella boninensis, Bonin Is.” 
“ Patella stearnsii.” 
“ Patella near stearnsii, Japan, 1892, only 8 found.” 
“ Patella nigrisquamata (?), Loo Choo Is., Yacyama Is.” 
“ Patella nigrisquamata (?), a var., Japan, 1892.” 
All the specimens sent are, in my opinion, referable to a single spe¬ 
cies which has long had a place in my cabinet as H. nigrisquamatus 
Reeve. 
Reeve’s locality for this species was “ Australia,” but this has 
never been confirmed and is doubtless an error. The same I think 
must be said of the additional locality, “ Concepcion Chili,” given 
by Mr. Pilsbry (in the Manual, XIII, 126), on the authority of Dr. 
W. S. W. Ruschenberger, for we cannot concede to any limpet a 
range so extensive as from Japan to Chili, and Japanese shells of 
which I am now writing are certainly true nigrisquamatus if figures 
and descriptions count for anything. I may add as negative evi¬ 
dence of a certain value that of several thousands of limpets from 
Chilian and Australian localities that have passed through my 
hands, I have never seen a specimen, young or old, approaching 
this species. 
With regard to P. boninensis, the differences on which Mr. Pils¬ 
bry relies are 3 in number (see Man. Conch. XIII, 132). The first 
geographical; but as nigrisquamatus has not been found in the same 
habitat as the original specimens of boninensis this distinction no 
longer holds. Secondly, the size of the central callus; but such a 
difference would hardly be specific, taken by itself, I should think, 
and moreover, it is not apparent in the series before me. Lastly, 
Mr. Pilsbry notes the brown streaks diverging from the head seg¬ 
ment of the central callus. These marks, however, are present in 
some of the specimens sent as nigrisquamata and absent in others 
sent as boninensis, showing either that the original collector was un¬ 
able to separate his shells accurately or else that the distinction is 
not a constant one. 
