Miscellaneous. 73 



Bronn's ' Klassen und Ordnungen des Thierreichs.' Biitschli asserts 

 justly that in all marine Kliizopoda, the Perforata and a great part 

 of the Imperforata, the entiie soft body is composed of completely 

 homogeneous plasma, and that in the Amcehae and Monothalamia 

 already mentioned by me no sharp line of demarcation exists between 

 the hyaline ecto- and the granular endoplasm, " as indeed is clear 

 from the fact that in certain Amoebfe, and also in PeJoynyxa, in 

 which usually no ectoplasm can be distinguished, under certain 

 circimistances such a hyaline external plasma-layer makes its 

 appearance, and this consequently must have been produced from 

 the granular plasma in the same way in which, locally bounded, a 

 hyaline pseudopodium is evolved from the bodj- of a Rhizopod con- 

 sisting of granular plasma."' 



I think I have now said enough upon this point, especially as I 

 have gone into it in detail in a more complete memoir on AmoebsB * ; 

 and I would here now only call attention to one thing, namely the 

 external limitation of the lihizopod-body. This, as is well known, 

 is naked, therefore not surrounded by any cuticle ; but it would 

 appear that by contact with water a stiffening of the plasma at the 

 periphery takes place, preventing its deliquescence, and also causing 

 an immediate closure of the cut surface in cases of artificial division. 

 When the protoplasm issues forth in a broad process in the form, 

 of pscudopodia, the firmer bounding portion dissolves in the advanc- 

 ing plasma to become re-formed at the same moment. Usually this 

 envelope is not perceptible even with the highest powers ; but in 

 some Amoebae, with a particularly tough slowly-flowing plasma, it 

 frequently attains a demonstrable thickness. This opinion also I 

 have put forward more in detail in previous writings, and I revert 

 to it here chiefly because, in my first memoir relating to this point f, 

 I overlooked, and in the second, while mentioning the fact J, I did 

 not give it sufficient prominence that long before me Wallich § had 

 set up and established exactly the same theory ; his view perfectly 

 agrees with mine, and he has also given an explanation of the pro- 

 duction of the nutritive vacuoles by assuming that a drop of water 

 is carried in with the nutritive bodies, and that exerts the known 

 stiffening action upon the portions of plasma surrounding the bodies, 

 so that thus every nutritive vacuole appears to be lined with an 

 ectosarcal layer. I think it may be regarded as strong evidence in 

 favour of the opinion here expressed that the English naturalist and 

 myself have come to exactly the same result quite independently of 

 each other. — Biologisches Centmlblait, Band vi. p. 5, March' 1, 1886. 



* " Studien iiber Amoben,"' in Zeitschr. f. wiss. Zool. Bd. xli. 



t " Beitr. zur Kenntn. der Amoben," in Zeitschr. f. wiss. Zool. Bd. 

 xxxvi. (^1882) ; and see Ann. & Mag. Nat. Hist. ser. 5, vol. ix. p. 106. 



J " Studien iiber Amiiben," /. c p. 190. 



§ Loc. cit. Wallich, in a recently published criticism of my work, 

 justly reproaches me with this sin of omission (Ann. & Mag. Nat. Hist. 

 ser. 5, vol. xvi. p. 215). 



