At a short distance above the mouth a double transverse filament, 

 resembling in colour the abdominal nerves of Pedinaria, surrouiids 

 the body : it s\vells out in each space intervening betvveen the 

 bands of cilia into a ganglion ; and from each of these gangiia there 

 pass on each side t\vo nerves to the adjoining band, while a lai'ger 

 filament proceeds up\vards to beyond the middle of the body, having 

 tvvo or three smaller ganglionic enlargements, from which filaments 

 are detached to the viscera. The whole of this system is seated 

 near the surface of the body. In the circular disposition of the 

 centrai filaments and gangiia, and in the regular radiation of nerves 

 from that centre, it resembies the nervous system oi Holothiiria and 

 Asterias among the Echinodermata. 



The comparatively iarge size of the cilia on the Bero'ė Pikus, 

 enabled Dr. Grant to observe their structure more satisfactorily 

 than in the microscopic animals on which they have previously been 

 particuhirly noticed. In the latter they appear likę flat tapering 

 filaments prolonged from the homogeneous cellular tissue of the body 

 to which they are attached, But in the Bero'ė it is evident that 

 they are not single fibres,but consist of severa! straight, short, trans- 

 parent filaments placed parallel to each other in a single row, and 

 connected together by the skin of the animal, likę the rays support- 

 ing the fin of a tish. These fins are of tlie šame breadth with the 

 band to vvhich they are attached, and extend irom the mouth to the 

 anus, there being about forty on each band. Under a lens the pa- 

 rallel fibres appear likę iransparent tubes, sometimes a little de- 

 tached from each other at their extremities, by injury done to the 

 connecting membrane, and at these parts the isolated spines pro- 

 ject stiffly outwards. When the cilia are in active vibration, there 

 isobserved along the middle of each band to vvhich they are attached, 

 a motion likę the continiied undulations of a fluid. Connecting 

 this with the analogy which may be deduced from the motion pro- 

 duced in the tubular feet oi Asterias and Echinus by the entrance 

 and exit of \vater sent into ihem by vessels destined for that ofBce, 

 it seems highly probable that the motions of the cilia of Bero'ė are 

 intimateiy connected vvith the streams passing along the bands, and 

 that hence an explanation may be obtained of one of the niost re- 

 markable phaenomena of animal motion, which is at the šame time 

 one of the most frequent occurrence among the less highly or- 

 ganizcd of animated beings. 



Dr. Grant's paper will be published entire, with a figure of the 

 animal, in the Society's Transactions, 



Mr, Yarrell detailed some observations on the changes of plumage 

 in Birds ; vvhich he illustrated by Notės on several species in the 

 Society's Gardens made by James Hunt, one of the Keepers. 



In his observations Mr. Yarrell pointed out three modes by which 

 changes in the appearance of the pluraage of birds are prcduced : 

 1. By the feather itself becoming altered in colour. 2. By the 

 bird's obtaining a certain portion of nevv feathers without shedding 

 any of the old ones. 3. By an entire or partial moult, in which 



