Pvn H,i I'UitlS

ARC A.
183
Algiers showing the transition of one of these species
from the other.
The accentuation of the name tetragona has also
perplexed many conchologists. There is no question
that, if it were formed into a Latinized-English word,
the accent would lie on the second syllable, as is the
case in pentagonal and hexagonal, and Dr. Latham was
quite right in saying that English quantities
Latin quantities.
are not
But tetragona being a Latin word, it
seems to me that the classical mode of accentuating
words written in that language, according to their
correct or accustomed quantity, ought to be used in
pronouncing such names as the present. This name
being derived from ycovla " an angle/' and having
been adopted by the Romans, as well as the Greek
combination of the same root with other numerals, the
penultimate syllable is long, and I have therefore placed
the accentuating mark over it.
I have now before me the original specimen of Turton's
A. reticulata, which he said was found in Lough Strangford
by his son-in-law, Dr. Macgee. It is not the A.
reticulata of Gmelin, but the A. barbata of Linne, and is
a rather common Mediterranean shell. Mr. Dillwvn
gave me two single valves, in a much worn state, received
by him from Miss Hutchins, as having been collected by
her in Bantry Bay, and which he sent to Montagu for
his inspection.
The paper in which they were wrapped
still bears the name " A. barbata " in the handwriting of
the latter naturalist. I do not consider this evidence
sufficient to include the species among our indigenous
mollusca. Collard des Cherres, however, has enumerated
it in his list of shells living on the coast of Brittany, and
it may therefore be looked for in the Channel Isles.
The Turtonian collection also contains a specimen of