Miscellaneous, 461 



to all vegetables. He observed that neither the odours of the fresh, 

 dried, and burnt sponges, nor the presence of ammonia in them, af- 

 forded proofs of their animality, and that there really is no more pe- 

 culiarity in their chemical composition than what likewise exists in 

 that of certain plants. 



Mr. Hogg therefore maintains it to be impossible to account the 

 Spongilla as belonging to the vegetable kingdom and the Spongia 

 to the animal ; and since he has become sure of the former, and since 

 the Spongia is now known to popsess neither one organ nor a single 

 property peculiar to an animal, he has been at length forced to ac- 

 knowledge the vegetable nature of the Spongia. 



Moreover, the fact of Dr. Grant having witnessed the locomotive 

 sporules of some of the sea sponges germinating and developing 

 themselves after the forms of their parent structures, at once decides 

 that they cannot be the nidus or matrix, or the fabrication or produc- 

 tion of any marine animal. 



Lastly, Mr. Hogg, considering to what order of plants the fresh- 

 water and the sea sponges should be referred, proposed to classify 

 them in a separate order " Spongiae," which ought to be placed 

 between the order Fungi and that of the Algae. 



MISCELLANEOUS. 



ON THE STRUCTURE OF THE FOLVOCINM, 



M. Ehrenberg observes, " that with respect to the organization of 

 the genus Volvox, all endeavours to acquire some knowledge of it 

 have only proved successful, now that observation has been at last 

 directed to the right depth (1833). Formerly the entire globule 

 was generally regarded as a single verrucose or ciliated animal- 

 cule, and its bursting considered as the reproduction of simple indivi- 

 duals. But this view leads to wonders and to contradictions ; it is 

 evidently erroneous, and the organic relations lie much deeper. Each 

 globule is a hollow monadier (Monadenstock) of many hundreds, nay, 

 thousands of minute animalcules ; and within this, several smaller glo- 

 bules are developed, which however are not single individuals, but also 

 Monadiers. The single animals are those small greenish warts 

 or points on the surface, and they resemble the Monads. Each ani- 

 malcule bears precisely the same relation as a single animal of Go- 

 nium pectorale; it possesses a gelatinous shield open anteriorly, 

 which when full-grown it can leave, and is connected by three to 

 six thread-like tubes with the neighbouring individuals. It is evi- 



