MI: MOM: <> i DALY! 1.1. x u 



a ;..: tii from time to time, phraseology which by no meant conveyed 

 lii- whole meaning. And it is further cvi<K>nt to us, that his observation* 

 ir more prolonged, and have attained on many point* a far 

 greater degree of exactitude and completeness, than those of eit her of tin- 

 authors we have just named ; and we shall show that one point of funda 

 mental importance has been clearly established by Sir J. G. Dalyell, al- 

 though neither Sara nor Siebold was able to make it out ; and that he ha* 

 thereby been led to a much more accurate conception of the whole pro- 

 cess, than they or their follower* have attained." 



The reviewer then refers to the series of observations by which Sir 

 John proved that the Hydra tuba springs from Afedmtr, and that the 

 Medu*er are themselves the progeny of the lli/ilra. The process by which 

 the latter breaks up into discs, and becomes separated into independent 

 animals, is minutely described by Sir John : and the reviewer considers 

 the fact that, while the topmost disc loses its circle of tentocula, a new 

 circle is developed upon the summit of the bulb that remains at the pile 

 of discs, a discovery of great importance, and one which has escaped the 

 notice of other observers. By this means, he says, " the original polyjii<l 

 body still remains, and may return to its polype life and gemmiparous pro- 

 duction, becoming the progenitor of a new colony of hydra, every one 

 of which may develop in its turn a pile of medusa-discs. Now, this fact, 

 our knowledge of which is entirely due to the persevering researches of 

 Sir J. G. Dalyell, is of fundamental importance in our philosophical in- 

 terpretation of this wonderful process." 



A third essay, entitled " Singular Mode of Propagation among the 

 Lower Animals," also appeared in the Philosophical Jmtrnal in 1835. An 

 essay "On the Regeneration of Lost Organs, discharging the Functions of 

 the Head and Viscera, in the Ilolothuria and Amphitritc, two Marine 

 Animals," was embodied in the Report of the British Association, 1840. 

 Another, on " The Reproduction of the Virgularia," appeared in the Nev 

 Philosophical Journal, volume 27 ; and a paper entitled " Examples of 

 Exuviation, or change of the Integuments of Animals," was read at the 

 meeting of the British Association, August 1850, and embodied in their 

 annual Report, 1851. 



