242 Ohservations on some points in ["oC'ii, mSTi^^o!'' 



lower sinus in opposite directions o, o', and consequently could not 

 possibly be under the influence of tbose marginal cilia. 



The courses produced by this second range meet in confluence 

 at the upper sinus (Fig. 3, o, o), and their continuation to the dorsal 

 lobe is interrupted at this point by two small ciliated processes {i, i), 

 which exercise such marked discrimination in their rapid selection 

 of particles from the general mass that are specially appropriate 

 for alimentary or budding purposes, and in rejecting others as 

 waste ; the whole mass passing beneath these processes into a 

 bilateral cavity (k), consimilar with the " arched " pair in Lacinu- 

 Jaria, and which we shall see has its representative in Stepha- 

 noceros ; and although the whole orifice and accessory organs 

 about the mouth appear to be one confused mass of cilia, the 

 introduction of carmine, or even an excess of the natural materials, 

 shows three distinct courses emanating from this cavity, first and 

 most important the refuse, in a dense volume, passing off and 

 blending with the current through the upper sinus (h) ; next a pro- 

 fuse percolation thi'ough the oesophagus (7) on to the manducatory 

 apparatus, and thirdly, a comparatively sparse and tardy current, 

 diverging along well-defined channels or chases beneath the lateral 

 margins of the dorsal lobe (Fig. 4, m, m), passing downward into 

 the peUet-cup beneath {n). 



The disc of Stephanoceros, with its five frontal lobes, is accepted 

 as an aberrant form of the trochal disc that characterizes the higher 

 forms of Botifera ; and it is stated that these five arms act like " a 

 common trochal disc by producing a vortex directing all particles 

 within its range to the mouth ;"* a statement based on an imperfect 

 acquaintance with the functions of the disc, either aberrant or nor- 

 mal, and having akeady shown their extent and limit in Melieerta, 

 we shall see that, though the methods here employed are in ante- 

 position, they serve the same general purpose, there by means of the 

 currents created by their marginal cilia, and here by means of the 

 great expanse of their setigerous lobes placing the animals respec- 

 tively in command of an extensive feeding area. They are both 

 constituted to act as prehensive appliances, and not as the imme- 

 diate cause in conducting nutritive particles to the mouth. 



The action of the Seise on the lobes both of Stephanoceros and 

 Floscularia is spasmodic, it creates no vortex, and it is only by 

 actual contact with these setai that fioating particles are whipped 

 within the area enclosed by the lobes, where by the same whipping 

 action they are twitched from point to point irregularly downwards 

 until they come within the range of a vortex that is due, not to any 

 action of the setw, but to a range of minute cilia in the funnel, 

 distinct from the foraging appliances. 



In Stephayioeeros the immediate control, together with the power 

 * ' Prit. Infus.,' p. 399. 



