318 MANUAL OF NATURAL HISTORY. 



long, depressed, without appendages, trans- 

 versely wrinkled ; a prehensile disk at each 

 end of body; mouth with horny jaws. Aqua- 

 tic. 



2. FAMILY. Simple Parasitic-Leeches (Phyllinidse). 



Body wide, depressed, wrinkled, simple above; 

 . a disk at the hind extremity only; mouth 

 proboscidiform, without jaws. Parasitic. 



3. FAMILY. Branchiferous Parasitic-Leeches (Bran- 



chellionidse). Body depressed, with a double 

 series of branched appendages on the back; 

 oral sucker distinct, separated from the body 

 by a constriction ; mouth without jaws ; anal 

 sucker large and concave. Parasitic on the 

 Torpeda 



III. SUB-CLASS. NEMERTOID- ANNELIDS (Nemertina). 



Body soft, mucous ; articulation obsolete ; apodal ; 

 head indistinct ; antennae none ; organ of locomotion 

 an expanded ventral disk, or not defined. 



I. ORDER. MOLLUSCOID- ANNELIDS (Dendroccela). 



Alimentary tube ramifying, arbusculiform ; a 

 single oral aperture ; anal aperture not distinct. 

 1. FAMILY. Aquatic -Molluscoids (Planariidse). 



Body depressed ; oral orifice on middle of 



lower part of body and proboscidiform ; eyes 



minute, rudimentary. Aquatic. 

 2: FAMILY. Terrestrial -Molluscoids (Herpidae). 



Body depressed, soft, attenuated in front ; 



oral aperture minute, at the extremity of 



