Dr. Griffith on the Sacculi of the Poly gastric a. 443 



the direction of particles in the alimentary canal is depicted ; and 

 the third, where the currents or motions of particles are indicated 

 in the distended intestinal canal. 



In addition to this, I refer to the Proceedings of the Royal 

 Prussian Academy of Sciences at Berlin for Feb. 1841*, wherein 

 is related an account of the observations of Dr. Werneck, which 

 agree in support of those of Prof. Ehrenberg ; nay, go further, for 

 Dr. Werneck renders more probable than heretofore, that the ali- 

 mentary canal exists in all the Polygastrica. 



I extract the following observations from the report of Prof. 

 Ehrenberg on Dr. Werneck' s discoveries as made to the Academy : 

 " Indeed what I, from caution, mentioned as only a supposition, 

 viz. that probably even in the monads (Bodo socialis) a distinct 

 anus, consequently an intestine, existed, whereby then the division 

 of the Anentera would be destroyed, is shown by Dr. Werneck to 

 be decided. He also has discovered the anus in Bodo grandis, 

 Prorocentrum micans, Cyclidium Glaucoma, whereby the family of 

 Pseudopoda only would remain without an alimentary canal. But 

 he has also seen in a Navicula [undulata) among the Bacillaria 

 group, a convoluted canal, which he considers as the alimentary 

 tube, filled with infusoria. Most interesting are the represen- 

 tations (Dr. Werneck's) of many varieties of intestinal canal with 

 their sacculi or globular pouches or recesses, which present ex- 

 actly the same appearances as those laid before the Academy in 

 1830, but lately denied by Prof. Rymer Jones and Meyen after 

 imperfect examinations." 



I shall now make some observations on the various state- 

 ments I have enumerated, and point out in what particulars 

 they disagree with my own experiments. In the first place, as 

 regards our not being able to see the alimentary tube, this I 

 cannot imagine to be any impediment or ground for our disbe- 

 lieving its existence. Doubtless the whole substance of the ge- 

 latinous bodies of these minute beings is very elastic, and the 

 walls of the tubes in which the alimentary matters are conveyed 

 are always in apposition except when alimentary matters separate 

 them. The outline of the intestine in many of the Infusoria de- 

 picted by Ehrenberg has been, without doubt, drawn from the 

 course which that illustrious observer has noticed the granules of 

 colouring matter and food to take. In fact, he says, f( In many 

 this direct observation is impossible, although the result, viz. the 

 colouring of the filled stomachs, is evidentf." The solid particles 

 cannot arrive at the sacs in which they are contained and accu- 



* Bericht liber die zur Bekanntmachung geeigneten Verhandlungen der 

 Kbnigl. Preuss. Akademie der Wissenschaften zu Berlin, im Monat Februar 

 1841. 



f Die Infusionsthierchen als vollkommene Organismen, page 2. 



2G2 



