among the Shetland Isles. 299 
its congeners and companions, all of which have very con- 
spicuous eyes. It is a somewhat remarkable coincidence that 
the shell of . stenostoma resembles a large Achatina acicula 
(a land mollusk), which is in the same category as regards 
these so-called organs of sight. The shells of P. carinata and 
P. nivalis are easily distinguishable. 
Among the rarer and more noteworthy mollusks procured 
this year were the following :— 
Montacuta tumidula. St. Magnus Bay and near Fetlar. 
Described by me from the Hebrides in the Reports of the 
Association for 1866. 
M. donacina, 8. Wood. A single valve from deep water 
in St. Magnus Bay. Another valve had been dredged by 
me at Falmouth in 1839. It is a rare Coralline Crag fossil. 
It nearest ally is UZ. substriata. 
Utriculus globosus, Lovén. A small living specimen oc- 
curred again in St. Magnus Bay. 
U. expansus, Jeffry. A few young specimens also in St. 
Magnus Bay. 
Odostomia Warreni, Thompson. Never having seen this 
shell in a fresh and perfect state, I considered it (Brit. Conch. 
iv. p. 143) a variety of O. obliqua. But the discovery of live 
specimens in St. Magnus Bay and near Fetlar enables me to 
separate the two as distinct species. O. Warrent has a 
shorter spire and more swollen whorls than O. obliqua, the 
suture is deeper, the strie are much stronger at the base of 
the shell, the whole surface is covered with most delicate and 
close-set microscopic spiral lines, and the umbilicus is well de- 
veloped and deep. The animal of O. Warreni has a peculiar 
foot; this is not plain and rounded at its extremity, as in 
O. obliqua, but is deeply bilobed or forked like the tail of a 
swallow. No other species of Odostomia, so far as I am aware, 
has a similar foot. One individual spun a fine glutinous thread 
from the middle of the sole of the foot, and kept itself suspended 
for some time from the surface of the water, with the point of 
the shell downwards. I found a dead specimen of O. obliqua 
on the same ground with O. Warrent. 
O. umbilicaris, Malm. A young specimen from St. Magnus 
Bay, nearly globular, and thus exhibiting the same distinctive 
characters as the adult. 
Stphonodentalium Lofotense and Cadulus (or Loxoporus) sub- 
fustformis again occurred, the former being more widely dis- 
tributed. Both inhabit the Mediterranean; and the latter is 
a Sicilian and Viennese fossil. I had an excellent opportunity 
of observing them alive and in active motion. The thread- 
like and extensile organs by which the Solenoconchia seize 
their prey are unlike the tentacles of any Gastropod, and their 
