422 ANNELIDA. 



grace of the original ; as usual, his description is admirable ; he remarks, 

 that a di'awing 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-Avater. 

 Taken by W. T., E. F., and R B. at Clifden. 



P. tretnelluris, Miill. 



At the end of April I have'taken numbei's 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 Miiller, but were otherwise identical. 



P. rosea, Miill. 



At the same time with Planaria cornuta two specimens of P. roaea 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. Miiller's specimens 

 were from the coast of Norway. 



P. Jlexilis, Dalzell. 



Ajn-il nth, 1848. — I found at Cultra, Belfast Bay, two Planarm 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. AVhen fully 

 extended they are 6 lines long, and at the head '1\ 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 Glossij)ho7iia-]ike vessels whitish ; the 

 ramifications outside them reddish-lilac. 



The motion of these Planarice is " very rapid, smooth, continuous, and 

 even,'' as Dr. Johnston describes that of the Plan, siihauriculata 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. snbauriculata. 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 



