C 437 ] 
XXXII. Observations on the genus Planaria. By J. R. Johnson, 
M. D. F. R. S. 
Read June 27, 1822. 
I b e g leave to lay before the Royal Society a few obser- 
vations on the genus Planaria, to which I have been more 
immediately led, from two or three species having been 
already described in the Linnasan Transactions under the 
genus Hirudo. 
I shall confine my remarks in the present paper to the 
following species : P. cornuta , P. torva, P. brunnea , and P. 
lactea , intending to give, at some future period, the farther 
history of this singular and extensive genus. 
P. cornuta. 
Planaria depressa, oblonga, nigro-cinerea, antice tentaculis 
instructa. 
Long. 4 lin. Lat. 2 lin. 
Body, blackish brown, convex above, flat beneath; fore 
part exsertile and retractile, with a tentaculum or feeler pro- 
jecting on each side of the. head ; tail pointed ; two ventral 
foramina ; numerous eyes. 
P. torva. 
Planaria depressa, oblonga, cinerea, subtus albida, iride 
alba. 
