Bkaumont — Fauna and Flora of Valencia Harbour, Ireland. 827 



over the surface of the body also. Of the latter, no mention 

 is made by Burger ; he merely says the head is pale yellow. 

 As to the former point, it is not a constant feature ; in some 

 specimens the area between the anterior and posterior furrows 

 is more deeply pigmented than any other part of the animal, 

 but I have seen individuals in which it is quite pale. The 

 reddish brown pigment consists of granules arranged in a fine- 

 meshed network. The gut, usually deep yellow, contributes to 

 the general colour-effect, as also the pinkish ovaries in ripe 

 females. Should future investigation prove these differences to 

 he constant, I would suggest the name Tetrastemma dissimulans 

 for the British form. 



In Yalencia Harbour this species was not found at all 

 abundantly. It was not discovered at all in 1895. In 1896 

 eight specimens were dredged; they were from 12-22 mm. 

 in length, and included examples of both sexes with genital 

 products approaching maturity. 



Distribution. — Plymouth (Riches, "W". I. B.); Isle of Man; 

 Falmouth (W. I. B.) ; Naples (Biirger). 



Tetrastemma RobertiansB, M'Intosh. 



Tetrastemma Rohertiance, M'Intosh (1874, p. 166). 



A single example was dredged in Valencia Harbour, in 1896, 

 close to the shore near Reenagiveen, in 1-2 fms. (muddy 

 ground, with Zostera and Ascidians). In material from the 

 same haul were several species of Turbellaria not obtained at 

 Yalencia on any other occasion. 



Our specimen was 15 mm. in length, and of stout figui'e. The 

 head of rhomboidal shape, as inM'Intosh's woodcut {op. cit. fig. 

 12, p. 167), but somewhat wider than there represented. At 

 each side of the head, just in front of the notches formed 

 by the anterior furrows, was a distinct angle, emphasized by 

 the presence of a projecting tuft of long cilia. On the ventral 

 surface, immediately behind the subterminal proboscis pore, was 

 a transverse fold. The cephalic furrows, which were indistinct 

 on the ventral surface in M'Intosh's specimens, were clearly 

 seen to run transversely for a short distance from the sides of 

 the head, and then bend forward (the cerebral canal probably 

 opening at the point where the course changes) to meet at the 

 posterior end of the mouth opening. The eyes were large ; 

 the anterior distinctly larger than the posterior. The colour- 



