PLANARIA. III!) 



propagating by ova, as I presume is the case, some short intervals have been 

 accidentally omitted. Many of the largest survive readily during several 

 months. 



These creatures feed alike on animal and vegetable matter, particu- 

 larly, as I think, on decaying leaves, when the intestines seem to be 

 coloured very dark. But the animal, on the intestines being emptied of 

 their contents, always becomes pure white. 



The Planaria ladca lives in society. Both in the natural and artifi- 

 cial state, it lurks among decaying leaves. I have seen between eighty 

 and ninet}' huddled together on the under surface of a large decaying 

 beech leaf. 



It is an animal of nocturnal habits. Let a large collection of miscel- 

 laneous matter be made from the places where it dwells, and emptied 

 into a capacious vessel holding a gallon and a half, by adding such a 

 quantity of fresh-water that a fourth or fifth part of the vessel above re- 

 mains clear and free, the Planariae beginning to move in the evening, 

 and gradually ascending the sides, may be observed in multitudes floating 

 supine on the surface. But many will be found to have descended in the 

 morning. 



PLATE XVI. 



FIG. 5. Planaria lactea, abstinent. 



6. Another specimen having fed, back. 



7. Belly. 



8. Head, enlarged. 



9. Ovum. 



PLATE XV. 



FIG. 4. Planaria lactea having fed, and the interanea full, enlarged, to shew 

 the distribution of the vessels. 



5. The same, anterior portion, shewing the eyes and the formation of 



vessels, more enlarged. 



6. Posterior portion on the same scale. It will be observed that here 



the middle part is omitted, and only both the extremities repre- 

 sented. 



