\ 
1886.] /s Littorina litorea Introduced or Indigenous ? 931 
_ use in the long lapse of time before the Proboscidian became 
e such.’ 
7 Very different is the case with the arched, cleanly-cut inguinal 
_ Space of the female ungulate, and its long, flexible-necked oft- 
spring, where the mammary gland is carried so easily by the 
mother, and is so accessible to the young. Here the anterior 
glands are the ones that have been discarded. 
These are mere speculations, for what can we do with such a 
subject? Surely not discard it altogether! Far better attempt 
even in the roughest way to interpret with what little light we 
have from the past, and fall wide the mark in our conclusions, 
than to pass unnoticed one fragment in the great history of life. 
-O: 
IS LITTORINA LITOREA INTRODUCED OR INDIG- 
| GENOUS? 
BY W. F. GANONG. 
e L is now nearly thirty years since Littorina litorea (Linn.), the 
; English periwinkle, was first reported from American waters, 
but the question as to whéther it has been recently introduced or 
2 Was an original inhabitant of our shores is still unsettled. This 
mollusk, though not known by naturalists to occur upon the 
= Seast of Acadia and New England previous to its discovery at 
3 ifax in 1857 by John Willis, is at present very abundant from 
_ the Gulf of St. Lawrence to Connecticut. 
3 Professor Verrill (Amer. Jour. Sci., iii, 1v, p. 133, 1874) says of © 
iti “Tt has been supposed by several writers that this shell (Z. 
4torea) has been recently and accidentally introduced from Eu- 
rope; but Dr. Dawson informs me that he collected it more than 
> ry years ago in the Gulf of St. Lawrence. It is abundant at 
Halifax, and we have other specimens from Kennebunkport, Me., 
Campton Beach, N. H., and Provincetown, Mass. There is 
_~@\'Y no sufficient evidence that it was not an inhabitant of our 
"Ores before the advent of Europeans, but local in its habitats, 
‘May have become more diffused in recent times by commerce, 
mit may have been overlooked formerly by collectors.” o 
-*h€ causes determining the geographical distribution of ani- 
S, and any contribution to it has its value. So peculiar and rie 
and plant life are a subject of the greatest importance to nat- 
