PLANARIA. 115 
Puate XVI. 
Fic. 10. Planaria arethusa, adult, dark grey. 
11. Adult specimen, brown. 
12. Head of a grey specimen from the General's Well at Binns, shew- 
ing the position of the eyes, enlarged. 
13. Specimen from the Dropping Well at Foulden, compressed between 
two flat plates. From the elegant pencil of the lady of Dr George 
Johnson, no less accomplished in the arts than her husband in 
the sciences. 
14. Lower extremity of fig. 10, severed September 14, regenerating a 
head on October 4. 
15. The same, haying become an entire and symmetrical animal, Octo- 
ber 24. 
16. Anterior extremity of fig. 11, severed September 14, regenerating 
the rest, as on Oetober 24. 
17. Anterior section of a specimen, as on October 24, which had been 
partitioned in three on September 26. 
18, Middle section of the same specimen, as on October 24, now rege- 
nerating both extremities. 
19. Posterior section of the same specimen, as on October 24, having 
regenerated a head. 
f—PLANARIA VARIEGATA.—Plate XVI. Fig. 20. 
Awaiting some future opportunity of verifying a few observations 
made on a single specimen, a place is here assigned provisionally to this 
animal. 
Length, an eighth of an inch ; extreme breadth, the twelfth of an 
inch. Figure of the body somewhat resembling that of the Planaria 
arethusa, but proportionally shorter and broader, like that which I for- 
merly denominated the Planaria panniculata, bemg enlarged in the 
middle. The head obtuse. Subtentaculated, lower extremity acute. 
Two large black eyes on the neck, considerably apart. Colour, alternate 
black and yellow belts. Motion smooth and gliding. 
This is a beautiful animal, plump and heavy, the belly flattened. 
