CASE OF SARCINA VENTRICULI. 359 



their angles only, as in the baccillarian genera. It also 

 explains why I could never detect more than four so united. 

 It may account for the circumstance that the SARCIK& were 

 found grouped as it were in colonies, in certain portions of 

 the ropy fluid, some drops containing numbers of them, others 

 none at all. 



Such is the structure, mode of reproduction and of de- 

 velopment, of this species of SARCINA. 



In tracing these out, it cannot but have been observed how 

 beautiful is the symmetry of all the arrangements how the 

 parts of the individual are arranged in the square how these 

 parts increase in numbers in a geometrical progression 1, 4, 

 16, 64, 256, and lastly, how the species propagates according 

 to the same law, 4 in the first generation, 16 in the second, 

 64 in the third, 256 in the fourth, 1024 in the fifth, and so on 

 with a rapidity peculiar to such a series of numbers. 



Is SARCINA an animal or a vegetable? is it one of the 

 infusorial Polygastrica, or a minute Alga ? In order to give 

 a satisfactory answer to this question, it becomes necessary to 

 analyse the groups to which SARCINA is most closely allied. 



Putting out of view for the present the FRAGILLARLE, DIA- 

 TOMACLE, and other gonioid organisms, the animal or vegetable 

 nature of which is yet a matter of doubt, I shall proceed to 

 Miiller's genus GONIUM, the genus of all others to which 

 SARCINA has the greatest affinity. 



The genus GONIUM consists of composite polygastric ani- 

 malcules, each corpuscle of the whole animal having, according 

 to Ehrenberg, the organisation of a monad, oral appendages, 

 visceral sacs, etc. Ehrenberg does not enumerate eye-points 

 among the characters of the family to which the GONIUMS 

 belong (VOLVOCIN.E). Without coming to any decision as to 

 whether the red points on certain species of GONIUM be really 

 eye-points, or merely optical illusions,* I may state at once, 



* It may be well to state, that the red dots do not appear in all the species, 



