ZOOLOGY AND BOTANY, MICEOSCOPY, ETC. 359 



development" of the Gregarine germs (Pseudonavicellse). Of the 

 structure of the spores we learn almost nothing ; in particular, the 

 remarkable thread-cell-like structure of the so-called polar corpuscles 

 appears to have quite escaped the author, and he takes no notice at 

 all of Balbiani's work on the Psorospermiae of fish. He has not 

 been able to observe any bursting of the spores and emission of an 

 amoeboid body. 



On the other hand, he has observed a method of development of 

 the spores which is carried out inside the bladder, but which he 

 gives with some reserve. It commences with the solution and absorp- 

 tion of the containing capsule, but then proceeds in two different 

 ways. Either the central protoplasmic part of the spore fuses with 

 the two polar corpuscles into a single protoplasmic mass, or the parts 

 remain distinct. In the latter case the spore-contents are said to 

 break up (in a manner which is not very intelligible) into two pieces, 

 seldom more. Finally, spore-contents, which have become granular 

 and vacuolated, are said to develope small, strongly granular plas- 

 modia, which become the protoplasmic structures first described. The 

 existence of another process of spore-development appears to the 

 author to be certain, seeing that at some time or another infection 

 must take place from outside. As already indicated, the author draws 

 from his results the conclusion that the structures which we have been 

 considering cannot be included with the Gregarinse, but must be con- 

 sidered as " spore-forming Myxomycetoid plasmodia," not, however, 

 exhibiting the entire characters of the group Myxomycetes. Hence 

 they are to be regarded as a tribe whose systematic position lies 

 between the Myxomycetes and Gregarines, a circumstance which 

 appears to the author to have a most important bearing on the rela- 

 tions which he represents to exist between these two groups. 



Morphology of Protozoa. — L. Maggi * again calls attention to the 

 differentiation of a mesoplasm between the ecto- and endoplasm, a 

 fact of deep importance in his view, and first discovered by him 

 in certain Araoebse and the genus Podostoma. The demarcation of 

 these three regions in the protoplasm of the body of certain Protozoa 

 appears to him of especial interest for this reason, that they exhibit an 

 analogy with the three blastodermic layers of the Metazoa. The 

 ectoplasm gives rise to the pseudopodia, which effect the relations 

 with the outer world; on the other hand, the mesoplasm supplies 

 the contractile vacuole, an organ of circulation, excretion, and exhala- 

 tion ; lastly, the entoplasm contains the " entoplasmatic organs," viz. 

 the digestive cavity, the nucleus, and nucleolus, the two last being 

 the organs of reproduction. Thus it is the mesoplasm and entoplasm 

 which support the vegetative functions of life. Grimm also f has 

 pronounced in favour of the view of the differentiation of a mesoplasm 

 and drawn the same parallel with the germinal layers of the Metazoa. 



G. Cattaneo | expresses opinions with regard to the morphological 



* Bollet. Scientif., i. (1880) pp. 81-3. Cf. Zool. Jahresber. Neapel for 1880, i. 

 p. 123. 



t ' Contributions to the Knowledge of the Simplest Animals,' 1877, in Russian. 



J Atti Soc. Ital. Sci. Nat,, xxii. (1880) p. 68 (2 pis.). Cf. Zool. Jahresber. 

 Neapel, torn, cit., p. 123. 



