Ciliary Motions in Reptiles and Warm-blooded Animals. 117 



do justice to the claims of others more fully, than can be looked 

 for in this brief notice. I may, however, here state, in the mean 

 time, that I have found the ciliary motion in several species of 

 asterias and sea urchin, in the aphrodita, the serpula, and other 

 genera of annelida, in addition to the one formerly examined ; 

 in the lymnea, planorbis, and other species of mollusca ; and 

 within the egg of the frog, as I had formerly observed it in the 

 egg of the newt. In the asterias the ciliary motion exists, 1st, 

 On the external surface ; %d, On the inner surface of the cavity 

 containing the viscera, to which, as is well known, the water has 

 access ; its membranous lining, which is prolonged into the so- 

 called respiratory tubes, and reflected on the coeca, exhibiting the 

 phenomenon also in these situations ; 3d, On the internal surface 

 of the stomach and coeca; and, 4th, Within the tubular feet. In 

 the aphrodita, I found it, 1st, On the external surface of the in- 

 testine and coeca, and on the lining membrane of the dorsal cells 

 in which the coeca are lodged ; and 2d, Within the intestine and 

 cceca, on their internal surface. A careful examination of various 

 species of actinias also shewed a striking correspondence between 

 the phenomena, as exhibited in these animals and the two last 

 mentioned ; and it may be remarked, that the appearances in 

 all these three cases, as also in the echinus, tend to support 

 the views of those physiologists, who conceive that the digestive 

 organs of these animals also exercise a respiratory function. I 

 have now also succeeded in detecting cilia on the surfaces pro- 

 ducing the currents in all instances except the sponge, even in 

 the larva of the batrachian reptiles, though in some cases these 

 organs are excessively minute, requiring a magnifying power of 

 300 diameters, and consequently considerable nicety of manipu- 

 lation, to render them visible. 



In suggesting the probability of the existence of this motion 

 in warm-blooded animals, as a provision for impelling fluids along 

 the surface of canals or cavities, independently of any muscular 

 contraction of their parietes, I mentioned also that I had sought 

 for the phenomenon, but without success, during the process of 

 incubation of the chick. I have since then repeated these in- 

 quiries respecting the chick, but still without being able to de- 

 tect the motion. It will be seen that Messrs Purkinje and Va- 



