Volvocina.] THE INFUSORIA. 121 



implies) within a second envelope or shell. The indi- 

 viduals of the genus are each of them provided with a 

 special lorica of their own, of the form of a little shield 

 (scutellum), but being of a social character, they have 

 besides a common envelope or gelatinous mantle (lacerna) 

 into which they retreat or aggregate, as occasion shall 

 require. They are deficient of both the eye and tail, 

 but they have a large filiform proboscis, which vibrates, for 

 the purposes of locomotion, &c. When the animalcules 

 are in a cluster, these proboscides give it an appearance of 

 being surrounded with hairs. The digestive sacs have 

 not yet been perceived. Self-division takes place in a 

 longitudinal direction. 



80. SYNCBYPTA volvox. The rolling Syncrypta. 

 Body of an oval form and green colour, with whitish rays 

 in the centre. Found generally in water drained from 

 conferva. Size l-2880th ; ditto of a clustered globule in 

 its crystalline tunic, hardly exceeding 1-5 70th. 



This berry-like cluster of animalcules, when rolling 

 through the water, is a beautiful object for the microscope, 

 and, with the aid of a little indigo, the numerous currents 

 it creates are readily perceived. The usual appearance 

 of the clusters, as viewed under the microscope, and 

 amplified 260 diameters, is given &tfig. 45. Fig. 44 repre- 

 sents a cluster magnified 400 times, and fig. 46 a cluster 

 as viewed by Ehrenberg, in its simplest state, when about 

 to sever into four. 



Genus XX. SYNURA. The ray globe Animalcules are 

 characterized by being destitute of the eye, but provided 

 with a filiform tail, which is attached either to the base of 

 its own lorica, or to the centre of the cluster to which it 



