4:88 Dr. Johnston's Contributions to the British Fauna. 



are placed here merely because we know of no other group to 

 which they can be so properly referred. 



1. Pl. flaccida. 



1. PI. elongata, depressa, brunnea, subtus albida : oculis nullis. 



PI. flaccida. Lamarck^ iii. 178. 



Fasciola flaccida. Muller, Verm. i. pt. ii. p. 67. 



Hab. The sea, near Berwick. 



Desc. Bod2/ five inches long, about four lines broad, and one 

 in depth, flat, a very little narrowed at both extremities which are 

 alike, opake, of a firmish consistence but very glutinous. The back 

 is of an uniform brown colour ; the ventral surface of a faint flesh 

 colour or nearly white. No ei/es. Mouth and anus terminal. 

 From the former we could not evolve any proboscis. 



We found two specimens of this species lying coiled up in the 

 cavities of a stone perforated with the Saxicava rugosa^ and which 

 had been dredged from deep water. They were exactly alike ; 

 and though they difiered in some slight particulars from the de- 

 scription of MuUer, yet these were not sufiicient to induce us to 

 quote his synonyme with any doubt. 



2. Pr-. UNICOLOR. 



2. PI. elungata, linearis, mutabilis, brunnea, unicolor ; ore albo. 



Hab. The sea, at the roots of the larger fuci, and under stones, 

 not uncommon. 



Desc. Body from four to twelve inches in length, one-eighth 

 of an inch in breadth, very contractile and polymorphous, soft, glu- 

 tinous, smooth, of an uniform dark brown colour, a shade lighter 

 on the ventral surface. There is a yellow line above the mouth, 

 which is itself white, vesicular, and terminal. Anus terminal. 

 When at rest it coils itself up into a round ball, and easily sepa- 

 rates into several portions, each of which will continue to live and 

 move for at least some days. A white thread-like intestine runs 

 from one extremity to the other, not visible when the animal is 

 entire, but which can be easily drawn out after it has separated 



