21(5 t»T'sci!TPTTON Of [Poh/flasfrlM^ 



movements, and its expansions the most difficult to discover. I have 

 found it on tufts of moss in marshy rivulets." 



In the internal soft substance, are seen near the posterior end, a 

 glandular body and hyaline globules. In moving, the position of 

 the shell may be perpendicular, or oblique to the surface of reptation. 

 the hexagonal depression are indistinct but large. The shell fracturea 

 along the lines of junction between the hexagons. 



Pamilt— BACILLAEIA. 



In re-writing the accoimt of this very extensive and important 

 family it will be advisable to retain much of the original text, and to 

 present most of the more recently obtained particulars together with 

 the various views entertained by authors, as an introduction to each 

 section, namely, the 'Desmidiacea and Naviculacea, into which the 

 Baeillaria are divided. 



The fii'st observers of this family considered its members animals j 

 but the greater number of modem naturalists regai'd them as plants, 

 and place them among the minute alga) ; hence it is, that we stand 

 indebted to the botanist for much of oiu' loiowledge of their forms 

 and localities. Again, some of the genera arc considered by philo- 

 sophers to be the connecting links between the animal and vegetable 

 kingdoms. 



Although, as before observed, there does not exist any distinct line 

 of demarcation to separate animals from plants, similar to that which 

 exists between organic and inorganic bodies, yet, with respect to the 

 animal or vegetable nature of the Baeillaria, after careful examination 

 of the proofs oifered on both sides of the question, it appears to me 

 that their position among organized beings, stands at present as 

 follows : — 



Vcgrtable Algse. 



Desmidieae. 



Baeillaria. 



Na\'iculacea. 



! 



Animal , Polygastrica. 



Professor Bailey, of New York, in his recent valuable "Microsco- 

 pical Observations made in South Carolina, Georgia and Florida," 



