106 DESCRIPTION OF [Poli/jastiicci. 



Family II.— CRYPTOMONADINA. 



The family Cryptomonadina exhibits all the charac- 

 teristics (and no certain or definite ones of any other 

 family) of the Monadina, together with a distinct gela- 

 tinous, membraneous, or hard induvium, or shell-like sub- 

 stance, termed a lorica, in which they are more or less 

 enclosed. Considering them as a family, their organization 

 has been determined as completely as that of the Mona- 

 dina, or even the larger Polygastrica ; although, in all pro- 

 bability, something more is yet to be learnt of the species 

 individually. The lorica, or integument covering these crea- 

 tures, is of diiferent forms; sometimes it is of the form of an 

 open shield {scutellum), at others of a closed box or a pitcher 

 (urceolus). Locomotive organs are clearly perceptible 

 in all the genera, excepting, perhaps, the genus Lagenella, 

 and even with this Dr. Warwick is of opinion that he has 

 discerned them. They consist of two delicate, filiform, and 

 generally retractile processes, issuing from the margin of 

 the mouth; they are capable of being put into very 

 powerful rotatory motion. We shall designate them, as 

 with the Monads, proboscides. The nutritive apparatus of 

 these creatures has not yet been demonstrated by the appli- 

 cation of coloured artificial food ; but with six or seven 

 species (nearly one-half the family) internal cells have been 

 discovered. In two genera, a sensitive system may be 

 presumed to exist, from a coloured spot or eye-like appear- 

 ance being present in the interior of the fore part of the 

 body. From the position of this organ of vision, the 

 dorsal line may 1)e readily conceived, so as to indicate a 



