PLANARIA. 115 



PLATE XVI. 



FIG. 10. Planaria arethwsa, 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, having become an entire and symmetrical animal, Octo- 



ber 24. 



16. Anterior extremity of fig. 11, severed September 14, regenerating 



the rest, as on October 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. 



/. PLANARIA VARIEGATA. Plate XVI. Fig. 20. 5 



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, being 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. 



