336 J. HOOD ON PLOSCULAKIA CUCULLATA. 



setae, and therefore probably not representing sense organs. 

 These pimples give a very characteristic appearance to the 

 creature when seen in front view, Fig. 2. The two smaller 

 ventral lobes are as shown in Figs. 1 and 2. 



When the animal contracts its head, the dorsal lobe folds 

 inwards first, and the two ventral lobes overlap it, leaving a 

 brush of setas projecting on either side, which finally are also 

 drawn into the cup. In expanding the ventral lobes appear 

 first ; then the dorsal lobe moves out very slowly, the creases 

 disappearing very gradually ; then suddenly the lobe flops out 

 in cowl-shape. 



The long, straight, stiff setse forming the outer rows stretch 

 out and radiate in all directions ; the very small setae of the 

 inner row are also straight and stiff, and prevent the escape of 

 the small organisms which have made the fatal mistake of 

 entering this alluring flowerlike cup. 



The semi-circular wreath of vibratile cilia at the bottom of 

 the vestibule is difiicult of observation, owing to the condition 

 of the skin ; there are, namely, a profusion of moveable greyish 

 granules floating in the fluid bel"ween the outer and inner mem- 

 brane of the skin that rush backwards and forwards in definite 

 channels at every movement of the animal, and render the 

 corona and anterior part of the body rather opaque. These 

 granules are more or less present in all floscules, but more con- 

 spicuously in F. amhigua, F. algicola, and F. cucullata. 



The coronal cup is very deep and the body elongated in 

 shape and constricted in the middle, forming an elegant waist. 



I have failed to find lateral antennae, but Mr. Dixon-lSTuttall 

 has observed a single antenna on the dorsal side of the neck in 

 specimen sent to him. Lateral canals and vibratile tags are 

 present, but I have not been able to find a contractile vesicle. 

 The remainder of the anatomy is quite normal and requires no 

 further remark. 



The animals inhabit large, clear, transparent tubes which 

 are fixed with marked preference to small filaments of a para- 

 sitic alga, when larger leaflets were present in abundance. 



I had the good fortune to see a male hatched, which has the 

 peculiarity of possessing a prominent dorsal antenna, as seen in 

 Fig. 3 ; all other males of Floscules, so far as observed, having 

 no such antenna ; it has also two small eyes close together. 



