<^ 12. INFUSORIA AND RHIZOPODA. 27 



wanting, its function is often performed by the mouth. According to 

 Ehreyiberg, the hifiisoria prAygastrica, such as we have just been describ- 

 ing, differ from the Infusoria rotatoria, in having a great number of stom- 

 achs, which connect by hollow peduncles with the mouth in the division 

 Anentera, and with the intestine in that of Eaterodela. This organiza- 

 tion, which, from its high authority, has generally been admitted by natu- 

 ralists, is not, however, met with in any infusorium.*^' 



The vesicular cavities in the bodies of these animals, and which have 

 been regarded by Ehrenberg as stomachal-pouches, never have a hollow 

 peduncle, either connecting with the mouth [Anentera) or with the intes- 

 tine (Enter odela). Indeed, it is doubtful if a digestive canal can be made 

 out in these Infusoria. 



The vesicular, irregular contracting cavities of their body contain a 

 clear liquid, evidently the same as that in which they live, which, with the 

 Astoma, has been absorbed through the surface of the body. But, with 

 those having a mouth and oesophagus, it is received through them, and 

 taken up by the yielding parenchyma of the body. 



If the methods of feeding of Gleichen and Ehrenberg are employed, 

 the colored particles are taken in by a vortical action of the water, caused 

 by the cilia surrounding the mouth. This water, with its molecules, accu- 

 mulates at the lower portion of the oesophagus, and so distends there the 

 parenchyma as to cause the appearance of a vesicle. Thus situated, the 

 whole has much the aspect of a pedunculated vesicle. But when, from 

 contractions of the oesophagus, this water escapes into the parenchyma, 

 it appears there as an unpedunculated globule, in which the colored 

 particles still float. When the Stomatoda are full-fed in this manner, there 

 appear many of these globules in various parts of the body; and thus sub- 

 stances previously ingested are taken up and disseminated throughout the 

 body. 



If the globules thus containing solid particles are closely aggregated, it 

 sometimes happens that they fuse together ; a fact which proves that they 

 are not surrounded by a special membrane. 



The solid particles of food of the Stomatoda, which are often the 

 lower Algae, such as the Diatomacece and Oscillatoria,and often other Infu- 

 soria, are .sometimes deposited in the parenchyma without being surrounded 

 by a vesicular liquid."^ 



From observations made upon Amcsba, Arcella and Difflugia, it appears 

 that the Rhizopoda ingest their food like the Stomatode Infusoria. 



1 Focke (Isis, 1836, p. 785) has already raised neck. ( Miiller's Arch. 1839, p. 80 ; also Monats- 

 doubts as to the existence in Infusoria of the bericht der Berhiier Akad. 18-11, p. 103.) But, de- 

 stomachs described hy Ehrenberg. Ehrenberg tailed as they nay be ( see £Are)i6ers- Abhandl. d. 

 has also opponents in Dujardin (Ann. des Sc. Nat. Ber. Akad. 1830, Taf. 1X1.; 1831, Taf. III.; also "Die 

 Zool. IV. 183.5. p. .364 ; V. 1836, p. 193 ; X. 1838, Infusionsthierchen," Taf. XXXII. XXXVI. ami 

 p. 230 ; also Hist. Nat. des Infus. 18-11, p. 57), in XXXIX.), they are not representations of nature. 

 Meyen {Muller's Arch. 1839, p. 74) and in Ry- The organ which in Trachelius ovum has been 

 mer Jone^ (Ann. of Nat. Hist. III. 1839, p. 105 ; taken by Ehrenberg ("Die Infusionsthierchen," 

 also, " A General Outline of the Animal Kingdom," p. 323, Taf. XXXIII. fig. xiii. 1) for a branching di- 

 1841, p. 56). gestive tube, has always appeared to me only as a 



He has attempted to replv to the objections here solid fibrous cord, traversing the soft parenchyma 



urged by very detailed illustrations of the organ- of the body, and by its ramifications presenting a 



ization of the Polygastrica, made by him and fFer- coai-se meshed aspect. 



* Bailey (Amer. Jour. Sc. May, 1853, p. 341) Imagine a bag made of some soft e.vtensible mate- 

 has recently published an account, accompanied rial, so thin as to be transparent like glass, ao sofl 

 with numerous figures, of a new animalcule, which as to yield readily to extension when subjected to 

 is so remarkable in this connection that I give here internal pressure, and so small as to be microscop- 

 his description. He says : " If the reader wiU ic -, this bag, filled with particles of sand, shells of 



