§ 12. INFUSORIA AND RHIZOPODA. 2T 



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

 Ehrenberg, the Infusoria polygastrica, such as we have just been describ- 

 ing, differ from the hifiisoria 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 Enterodela. 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 Ehi-enberg as stomachal-pouches, never have a hollow 

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

 tine (Enterodela). 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 vri-ious 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 Diatomaceae and Oseillatoria, and often other Infu- 

 soria, are sometimes deposited in the parenchyma without being surrounded 

 by a vesicular liquid.^ 



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

 that the ßhizopoda ingest their food like the Stomatode Infusoria. 



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

 doubts as to the existence in Infusoria of the bericht der Berliner Akad. 184i, p. 103.) But, de- 

 stomachs described by Ehrenbe.r^. Ehrenberg tailed as they may be ( see iArenöec^ Abhandl. d. 

 has also opponents in Dujardin (Ann. des Sc. Nat. Ber. Akad. 1830, Taf. 111.; 1831, Taf. III.; also "Die 

 Zool. IV. 1835, p. 364 ; V. 1836, p. 193 ; X. 1838, lufusionsthierchen," Taf. XXXII. XXXVI. and 

 p. 230; also Hist. Nat. des Infus. 1841, p. 57), in XXXIX.), they are not representations of nature. 

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

 mer Jones (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 reply 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 fV^er- coarse meshed aspect. 



* Bailey (Amer. Jour. So. May, 1853, p. 341) imagine a bag made of some soft extensible mate- 

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

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

 ]s 80 remarkable in this connection that I give here internal pressure, and so small aa to be microscop- 

 hia description. He says : " If the reader will ic ; this bag, filled with particles of sand, shells of 



