242 [August, 



Habitation. Beneath stones, flower-pots, and boxes, in gardens in Philadel- 

 phia, and under fragments of wood, bark, old logs, etc., in forests in the neighbor 

 hood of Philadelphia. 



Remarks. This is the first terrestrial planaria which has been detected in 

 North America. I accidentally discovered it first beneath several flower boxes, 

 and pots in the small garden attached to my residence in this city, since which, I 

 sought for and found it in the hilly woods bordering the Wissahicon Creek and 

 Schuylkill River. In its movements it resembles a slug (Limax,) and like this 

 leaves behind it a mucous trail. When in motion, the anterior portion of the 

 body is much elongated, and very narrow, and the portion anterior to the eyes is 

 recurved. Frequently it raises the anterior third of the body from the ground, 

 moving it from side to side as if in search of something. The recurved portion 

 inferiorly, is flat, with the edges often inflected. 



When at rest, the body is contracted into an oblong form, and the head lies 

 doubled upon the back. The longest will contract to 2i lines in length by i a 

 line in breadth, and jrd line thick posteriorly, and |th line wide anteriorly. 



The coloring matter upon the back is arranged in faint transverse annuii, accu- 

 mulating upon each side of the middle into a longitudinal line, and a transverse 

 spot about the centre. 



The eyes are globular, apparently composed of a vitreous humor, two-thirds 

 enveloped with a black pigment. They are situated laterally, the l-lOOth to the 

 l-48th of an inch posterior to the extremity of the head, tnd measure about the 

 l-500th in. in diameter. 



The mouth is inferior and a little posterior to the centre. (Esophagus keg-shaped, 

 about l-50th in. long. From the acute tail end is secreted a delicate mucou sthread. 



The planaria appears not to like the water, for although it will live for some 

 hours beneath the surface, when prevented from rising, yet it always seeks to 

 leave it and remains out when it has escaped. 



In the same forest localities with the planaria, is found an insect larva, possess- 

 ing similar habits, which upon careless inspection might be mistaken for it. The 

 movements of the larva are more rapid and vermicular. 



PLANARIA, Muller. 

 Sui-geiius nov. Bdelloura.* 

 Characters same as Planaria, without tentaculae, and the posterior extremity of 

 the body separated by a constriction serving as a disk of attachment. 



5. Bdelloura parasitica, n. s. 



Body milk white, with a faintly yellowish intestine showing through the trans- 

 lucent integument, smooth, thin, lanceolate, or spatulate ; anteriorly narrowed, 

 obtuse ; lateral margins, thin, undulating ; constricted portion posteriorly trun- 

 cated, nearly as broad as the middle of the body. Eyes two, reniform. (Eso- 

 phagus simple, cylindrical, campanulate when protruded. 



Length from 3 to 10 lines; breadth 2-5ths to 23th lines. The longest may 

 contract to 6 lines by 3j lines. 



Habitation Parasitic upon the King Crab, Polyphemus occidentalis. Lam. 



*fibiXKa, a leech ; goi tail ; because the animal adheres by the tail like a 

 leech. 



