446 Dr. Johnson’s observations on the gems planaria. 
by themselves, and two or three, notwithstanding their pre- 
vious artificial division, divided naturally, as at jig. 9. 
Having frequently noticed several full-grown Planarice 
with the head and tail of a greyish white, the rest of the body 
being brown or black, I should, without the knowledge of 
this re-productive property, have been led to consider them 
a distinct species. 
In reference to the P. lactea, Muller says ; “ Unicum 
exemplar cujus cauda in duos lobos acutos fissa erat reperi, aliud 
absque oculis, et interaneis conspicuis, mere lacteum ; cceterum 
idem.” It seems he was not aware, or I think he would 
have noticed it, that the circumstance of these Planarice being 
without eyes, &c., was occasioned by their having undergone 
a natural division, in order to their becoming distinct and 
separate animals. 
J. R. JOHNSON, M. D. F. R. S. and L. S. 
Bristol , 
September 24, 1821. 
EXPLANATION OF PLATE XLIX. 
Fig. 1. P. cornuta, front view, natural size. 
2. P. torva. 
Do. 
Do. 
3. P. brunnea. 
Do. 
Do. 
4. P. lactea , 
Do. 
Do. 
5. Do. with its egg or capsule. 
6 . Back view of P. torva, showing the ventral fo 
ramina. 
7. P. cornuta , about to undergo a natural division. 
8. P. torva. Do. Do. 
