Hyatt.] 48 [March 6, 



The author finds the integuments in Flagellata to consist of at 

 least four distinct layers, some of these layers having a curiously 

 close resemblance to cellular tissues as every investigator who 

 has seen them can also testify. He has, however, tried to de- 

 monstrate a true alimentary canal with large, perhaps respiratory 

 oesophagus, an anal or intestinal extremity which opens extern- 

 ally at the posterior pole of the body, specialized reproductive 

 organs, and a water system, and has delineated the production of 

 germs from the nucleus in a special reproductive tube in Hete- 

 romitus, a biflagellate form. It is probable, that the young he 

 observed in the oviducts, like those described by authors in Vorti- 

 cella, and other Protozoa were parasites, and it is difficult to credit 

 the existence of some of these organs in the Flagellata, when al- 

 most all observers unite in asserting, that with the exception of the 

 stomach pouch, intestine and anus, the pulsating vesicle, and the 

 nucleus and so-called nucleolus, there are no other organs even in 

 the highest of the Ciliata, and also that the integument or ectos- 

 arc is a simple layer differing only very slightly from and really 

 forming a continuation of the endosarc. 



Huxley's observations made with the view of testing the uni- 

 cellular nature of Protozoa in Jour. Linn. Soc. 1876. p. 203, sus- 

 tain Oken's opinion and Von Siebold's definition. 



Onus, Grundztige der Zoologie, after giving the best summary 

 we have yet seen of the evidence upon these points, concludes as 

 follows, in the words of Haeckel, " der Infusorienlieb bietet dem- 

 nach einen Complex von Differenzirungen, die wir einseln als 

 Attribute echter Zellen auftreten sehn." " The body of the 

 Infusorian (alluding exclusively to the Ciliata) offers, there- 

 fore, a collective assemblage of differentiations, which we see 

 appearing separately as attributes of true cells " (among the 

 Metazoa.) This conclusion is sustained by the general morphology 

 of the cell, the late brilliant discoveries of Metschnikoff upon 

 resorption and intra cellular digestion, the habits of wandering 

 cells and white-blood corpuscles and the structure of some eggs. 

 For example, the structure of the eggs of Insects and the origin 

 of the blastoderm from true amoeba-like cells which originate 

 either in the vitellus or directly from division of the nucleus. 

 Authors differ on this last question, but not on the others, and 

 have concurred in Weissmann's discovery, Zeit. Wiss. Zool. vol- 



