162 Transactions of the Society. 



ordinary flexible processes, perched one on each side of the summit 

 of the dorsal lobe. I cannot yet hazard a suggestion as to the 

 function that these processes perform. 



No other species has anything in the least like them. They 

 appear to be hollow, and to communicate with two sub-spherical 

 spaces lying between the two surfaces of the dorsal lobe. Fine 

 muscular threads pass down and across them, and the animal 

 can contract and expand each independently of the other and 

 throw them into all kinds of positions. The upper end of each 

 seems to be separated partly from the remainder by a constriction 

 from which a muscular thread runs down to the base ; but though 

 I have tried many objectives and every kind of illumination, I have 

 failed to see the slightest trace of setae in them. Besides, if these 

 were two antennae, they would be in a unique position ; all other 

 Floscules have their pair of setae-bearing antennae on their sides 

 below the trochal disk, while the dorsal surface carries a solitary 

 setigerous eminence on the medial line. 



Mr. Hood tells me that he has seen both a young and an 

 adult specimen of F. Hoodii discharge through these processes 

 granular matter which gathered round their free extremities, and 

 which the creature got rid of with difficulty. 



Frequently when the animal is fully protruded from its case, 

 one of the processes is invisible, having been permitted to collapse 

 as it were on to the dorsal lobe. Then the upper end of the 

 visible process may be seen to move so as to form almost a right 

 angle with the lower portion ; or again, the whole of the one 

 process will be slowly lowered on to the dorsal lobe while the other 

 is gradually distended and raised. 



The thickened rim of the three lobes carries a double fringe 

 of setae, set just as they are in F. trifoUum, the larger row stretching 

 outwards and the smaller inwards ; and I have on several occasions 

 seen a rapid flicker run all along the smaller setae, not constant or 

 regular enough to produce the phenomenon of " rotation," but still 

 a very obvious motion of each separate seta. The gape of the 

 mouth-funnel alters constantly, now opening in the characteristic 

 way shown in the figure, plate III. fig. 2 (which is the ventral 

 view) and then closing by means of its many muscular threads, 

 so as to reduce the aperture to a mere slit, or even to shut 

 it up in puckers. If the animal is so placed that the line of 

 sight strikes the middle of the dorsal surface obliquely, it will 

 be seen that a nearly transparent ridge or buttress runs up from 

 either side of the body to the back of the dorsal lobe, ending 

 at the base of the process. One of these is shown in the side view 

 (plate III. fig. 1). Between these two ridges there is a deep 

 hollow, bounded above by the dorsal lobe and below by the rounded 

 surface of the body. At the lowest portion of this hollow, and 



