246 Mr. Darwin on several Planariae, 



7. Planaria elongata. 



Alimentary and genital orifices obscure. Ocelli absent : posterior 

 extremity very obtusely rounded. Above " umber- brown," with a 

 narrow medial line of darker brown ; sides narrowly edged with pale 

 brown, bordered with the umber-brown ; beneath pale brown. 

 Length when crawling 5 inches, when closely contracted l^yths of 

 an inch, breadth when crawling ^^ths, when contracted y%ths of an 

 inch. 



Hab. On rotten wood in mountain-forests : C. Tres Montes, lat. 

 46° 30' S., Western America (December). 



8. Planaria semilineata. 



Body convex. Above greenish black, with minute white punc- 

 tures ; on anterior half of body four parallel bands of " gall-stone 

 yellow," of which only the central and approximate pair are pro- 

 longed into the posterior half of body : foot leaden colour, with co- 

 lourless spaces for the orifices. 



Hab. Under stones, on one of the Chonos Islands (north of C. Tres 

 Montes) (December). 



9. Planaria maculata. 



Edges of the body very thin ; breadth nearly uniform. Upper sur- 

 face quite black, with numerous, oblong, variously sized spots of 

 yellow : foot mottled white and black. Length when crawling l T ? ths ; 

 breadth y%ths of an inch. 



Hab. Forest of Valdivia (February). 



10. Planaria Tasmaniana. 



Mouth-sucker widely extensile : alimentary orifice placed nearly 

 in centre of the body ; genital orifice y\jth of an inch posteriorly, but 

 when the animal crawls it is ^ths of an inch distant. Genital ori- 

 fice very distinct, submargined. Ocelli scattered round the entire mar- 

 gin of the foot, but most frequent at the anterior extremity. Both ex- 

 tremities pointed. Colour dirty '* honey-yellow," with a central dark 

 brown line bordered on each side with a broader line of pale " umber- 

 brown :" foot quite white. Length when crawling l T 5 G ths ; when 

 contracted ftths of an inch. 



Hab. Beneath decayed trees in the woods of Van Diemen's Land : 

 frequent (February). 



I will now briefly describe five marine species of Planaria, which 

 are remarkable, either as presenting novel points of structure, here- 

 after probably forming the types of new subgenera, or from the 

 situations which they inhabit. 



1. Planaria (?) oceanica. 

 Plate V. fig. 1. Under-surface magnified. 

 Anterior extremity neck-shaped, with two ear-like processes. 



