128 MICROSCOPICAL MEMORANDA. 



fossil Infusoria of Ehrenberg, and occupying the same place in the 

 vegetable kingdom as those do in the animal. Ninth Report Brit. 

 Assoc. 1840. 



Are the Closteria Animals or Plants ? Ehrenberg enumerates the 

 following reasons for considering the Closteria as belonging to the ani- 

 mal kingdom. They enjoy voluntary motion, they have apertures at 

 their extremities, they have projecting permanent organs near the aper- 

 tures, which are constantly in motion, and they increase by horizontal 

 spontaneous division. Dr. Meyen, who was of the opposite opinion, 

 mentions, as the most important observations in favour of their vege- 

 table nature, that their structure is exactly similar to that of the Con- 

 ferva: their formation of seed, and the development of this seed, is 

 like that of the Conferva. The occurrence, moreover, of amylum in 

 the interior of the Closteria, with \vhich they are frequently nearly 

 filled, is a striking proof of their being plants ; they have no feet. 

 What Ehrenberg regards as such, are molecules, having a spontaneous 

 motion, which occur in great number in Clos. Trabecula, and quite fill 

 a canal the whole length of the plant. Their function is difficult to 

 determine, but they also occur in very many Conferva, and may perhaps 

 be compared with the Spermatozoa of plants. Ann. Nat. Hist. Vol. 

 7F.ji.-7L 



Griffiths on Ephedra. He is of opinion, that the ovulum is. as 

 described by Mr. Brown, naked. The first species referred to had a very 

 silicious stem, without stomata, unless certain discs blocked up with 

 some hard matter (silex ?) are to be so considered ; this he believes 

 to be the correct view, inasmuch as the other species, which has no 

 silicious deposit, has stomata of the ordinary structure arranged in a 

 similar manner. Proc. Linn. Soc. 1841. 



Diameter of the Globules of Human Blood. For the sake of reference, 

 we insert the measurements of the globules of the human blood, given 

 by various observers : 



Hodgkin .......................................... 30 1 00 of an inch. 



Jurine, in a 2nd measurement 



Bauer .......................... ................... TTOO 



Wollaston 



Kater 

 Ditto 

 Prevost and Dumas 



The thickness of the particles, which is perhaps not so uniform as 

 the diameter of the discs, is on an average to this latter dimension, as 

 1 to 45. Hodgkin and Lister's Micros. Observ. on the Blood, $c., Phil. 

 Mag. Vol. II, p. 133. 



