422 
ANNELIDA. 
grace of the original ; as usual, his description is admirable ; he remarks, 
that a drawing was fortunately made from his specimens, two in number, 
upon the day on which they were procured, as next morning they had 
disappeared, having been dissolved in the sea-water. 
Taken by W. T., E. F., and R. B. at Clifden. 
P. tremellaris, Miill. 
At the end of April I have'taken numbers of this species from the under 
sides of stones in pools among the rocks at Rockport, Belfast Bay. The 
specimens were rather under the size — “ long. 9 lin. lat. 4 lin.” — attributed 
to the species by Muller, but were otherwise identical. 
P. rosea, Miill. 
At the same time with Planaria cornuta two specimens of P. rosea were 
taken. This species has not yet a place in the British Fauna, but it was 
obtained on the coast of Anglesea last autumn by Mr. M‘Andrew and 
Professor Edward Forbes when dredging there. Muller’s specimens 
were from the coast of Norway. 
P. Jlexilis, Dalzell. 
April 14 th, 1848. — I found at Cultra, Belfast Bay, two Planarice of this 
species, adherent to the under side of a stone between tide-marks, and 
brought them home in sea-water to be observed at leisure. When fully 
extended they are 6 lines long, and at the head 2^ broad, becoming 
thence gradually narrower. Eyes commencing at the distance of a line 
from the anterior extremity of the body ; all extremely minute, but 
differing in size ; disposed irregularly in a somewhat crescentic form on 
either side a transparent circle. The vessels along the centre of the body 
are prettily ramified, like those of the genus Glossiphonia, as represented 
by Moquin Tandon (Monog. Hirudinees, pi. 14, 2nd edit.). Outside this 
central distribution of vessels, the body, to very near the margin, is most 
minutely and beautifully ramified all over ; the whole worm presenting 
the appearance of a Glossiphonia, “set” — in jewellers’ language — in the 
centre of a Planaria which broadly expands on every side. This appear- 
ance is literally “ shadowed forth ” in Sir J. Dalyell’s figure 2. The 
colour of one of my specimens, which lived for twelve days in a phial 
of sea-water, changed about once in thirty-six hours, was during the 
time transparent, with the central Glossiphonia-like vessels whitish ; the 
ramifications outside them reddish-lilac. 
The motion of these Planariee is “ very rapid, smooth, continuous, and 
even,” as Dr. Johnston describes that of the Plan, subauriculata to be 
(Loudon’s Mag. Nat. Hist., ix. 16, f. 2), and with which species I cannot 
but consider the P. Jlexilis identical. The differences set forth in Dr. 
Johnston’s diagnostic characters of the two, are, that the body of P. Jlexilis 
is “ semicircular in front,” that of the other “ obtuse,” and that the inter- 
vening space between the eyes is like the rest of the body in P. Jlexilis ; 
but that “ a clear circular spot to each of the two clusters of eyes ” exists 
in P. subauriculata. The individuals examined by me are occasionally 
obtuse, and occasionally semicircular in front, and present themselves 
exactly of the forms represented by both authors, as well as in innumer- 
able other shapes. The position of the eyes is the same in both the 
supposed species ; the clear “ circular spot ” to each cluster may either 
have escaped being recorded by Sir J. Dalyell, or possibly may not have 
existed in his specimens ; mine have both clusters of eyes within one 
