Scientific Intelligence. — Zoology. 385 



the drop of water in which they swim, with colouring mat- 

 ter of indigo, of lac, of carmine, or sap-green, they fill their 

 single stomachs with it in the space of one or two minutes. This 

 is very easily and distinctly seen in some of the most frequent 

 of these creatures, as Kolpoda cuculltis, Cyclidium glaucoma. 

 Dr Ehrenberg has also observed in some of the lowest of the 

 infusoria, the formation of a reticular ovarium surrounding 

 the ventral sacs. He could not discover any circulation or ves- 

 sels in the Paramacium aurelia, as asserted by Gruithuisen. 

 But it is certain that the BacillaricE, particularly the Closte- 

 rium lunula of Nitzsch, and acerosum ( Vibrio lunula, Miiller, 

 and Vibrio acerosum, Schrank), are provided with feet in the 

 form of papillae, at both ends of the body, by means of which 

 their progressive motion is performed. It may also be noticed, 

 that the part in the body of the Brachiones named heart, first 

 by Corti, and afterwards by Bory St Vincent, is not so, but is, 

 according to Nitzsch and others, a maxillary apparatus. Dr 

 Ehrenberg is the first who has observed in all Brachiones in the 

 Megahtrocha, Bory, and in a whole family of ciliated, not ro- 

 tating Furcularia, 1 to 12 eyes. Lastly, Dr Ehrenberg is of 

 opinion, that the compound infusoria supposed to have the same 

 structure as ascidia, have truly a mouth at their anterior, and 

 an anus at their posterior extremity. — Isis, Heft 3. 1830. 



23. On the Power of Horses. By B. Bevan, Esq. — To deter- 

 mine the average power of horses under different kinds of labour, 

 has been a subject deemed worthy of the inqu'u-ies of scientific 

 writers. It is one of those points which can be determined only 

 by experiment. The power to be maintained depends upon the 

 velocity, and various formulse are given by writers. The best 

 of these is that given by Professor Leslie. In the period from 

 1803 to 1809, I had the opportunity of ascertaining correctly 

 the mean force exerted by good horses in drawing the plough, 

 having had the superintendance of the experiments on that 

 head at the various ploughing matches, both at Woburn and 

 Ashridge, under the patronage of the Duke of Bedford and the 

 Earl of Bridgewater. I find among my memoranda the result 

 of eight ploughing-matches, at which there were seldom fewer 

 than seven teams as competitors for the various prizes. The 

 first result is from the mean force of each horse in six teams, of 



