with an Account of their Habits. 247 



Ocelli, I believe, absent. Posterior extremity broadly rounded. Mem- 

 branous margin of body jagged. Length -y^ths, °f an mcn - Colour 

 pale, uniform. Near the neck there is a quadrangular, internal, 

 clear space, apparently lined by a membrane, within which there is 

 a dark-coloured spot, and externally close by it an orifice, which the 

 animal can dilate and contract at pleasure. Close behind this there 

 is an internal oval space, within which there is a second dark spot 

 united to a delicate vessel ; I was unable to distinguish any orifice 

 near this point: these organs form, I presume, the reproductive 

 system. Close behind these organs there is a dark space formed by 

 the union of eleven, branching, intestinal cavities, in the centre of 

 which there is a longitudinal orifice situated rather behind the centre 

 of the body. Through this orifice the animal can protrude a folding 

 mouth-sucker : when it begins to unfold it is seen to be drawn into 

 eight folds, as represented at (B). 



Hab. Open ocean, lat. 5° S., long. 33° W. (February). 



This I believe is the first instance of a species of this genus 

 being found in the open sea, at the distance of 150 miles from 

 the nearest part of S. America, and 80 miles from the small 

 island of Fernando Noronha. 



2. Planaria (?) formosa. 



Body much depressed, oval. In the posterior half, on the under 

 side, there is a very large alimentary orifice with folding lips (but 

 apparently with no exsertile mouth-sucker), from which the two 

 main intestinal cavities branch. Near the anterior extremity there 

 is a minute orifice, and between it and the mouth a second orifice : 

 these the animal can dilate and contract ; they lie over an opake, 

 wedge-formed, internal mass, and form, I presume, two genital orifices. 

 Back dotted with purplish red, with a central band of " vermilion- 

 red," edged with white : this band sends off three branches on each 

 side ; at the extremity of each of the two anterior branches there is 

 a longitudinal group of black ocelli, and before these two other cir- 

 cular groups, forming together four groups of ocelli. Length when 

 extended half an inch. Inactive in its movements. 



Hab. On corallines, at a depth of 30 fathoms, in southern Tierra 

 del Fuego (December). 



3. Planaria^.) macrostoma. 



Plate V. fig. 2. Under-side magnified. 



External alimentary orifice situated in the posterior half of body : 

 mouth-sucker nearly subcylindrical, bell-shaped, very long ; when con- 

 tracted within the body it lies in a serpentine position ; when partly 

 protruded it has the figure as represented ; when fully extended it 

 tapers only slightly from its mouth to its base, and is so long, that 

 the animal can pass it from the under surface over the entire width of 

 its back. Its base is united, in the middle of the body, to the three 

 principal branches of the intestinal cavity ; the two posterior 

 branches unite and form a ring, enclosing the space in which the 



