^58 DESCBiPTiox OF \^Polygastrica. 



tliey move quite horizontally, at others vertically, and then again on 

 theii- edges, revolving Hke a wheel. A magnifying power of 200 

 diameters is siiffieient for general examination ; but to exhibit all the 

 structui'es showna in the engTa\ings, four times that power will be 

 requii-ed. Foxmd in clear water, salt and fresh, near the surface. 

 Discovered by Miiller, in clear water, at Copenhagen, 1 773. Size of 

 animalcule from 1 -460th to 1-11 50th ; ditto of tablet, not exceeding 

 l-280th. 



Goisixm punctatum. Body composed of green corpuscles, spotted with 

 black, and enclosed within a ciystalline lorica. Found amongst con- 

 ferva. Size of animalcule 1 -4600th; a tablet of 16, 1-5 70th in 

 breadth. 



G. tranquiUum. Body composed of green corpuscles within a crys- 

 talline lorica, as shown at figiu-e 43. Size 1 -2880th; a ditto tablet 

 of 16, from l-140th to 1 -220th in breadth. Tablet sometimes twice 

 as broad as long. 



G. hyaUnmn. Body composed of transparent corpuscles within a 

 crystalline shell. Found in stagnant water. Size 1 -300th; ditto 

 tablet of 20 to 25, l-6000th in breadth. 



G. ghucum. Body composed of blueish-green corpuscles within a 

 crystalline shell. The tablets vary in the number of animalcules — 

 namely, from four- to sixty-four. Found in sea Avater. Size 1 -5000th; 

 ditto tablet, 1 -500th in diameter. 



Genus Synchypta. The double Iwicatecl globe Animalmles. — This 

 genus of the family Yohocina is mainly characterized by its secreting 

 or hiding itself (as the name implies) within a second envelope or 

 shell. The individuals of the genus are each of them pro\-ided with 

 a special lorica of their own, of the fonn of a little shield {smtellum), 

 but being of a social character, they have besides a common envelope 

 o:- gelatinous mantle (lacerm) into which they retreat or aggregate, 

 as occasion may require. They are deficient of both eye and tail, 

 but they have a large filiform proboscis, which vibrates, for the pur- 

 poses of locomotion, &c. When the animalcules are in a cluster, 

 these proboscides give it an appearance of being siurounded with 

 hairs. The digestive sacs have not yet been perceived. Self-division 

 takes place in a longitudinal direction. 



With this genus Dujardin would identify his Cryptomoms {Tetra-2 

 hcena) p. 144. 



