OLIVE : MONOGRAPH OF THE ACRASIEAE. 
455 
occur in Labyrinthula and Diplophrys among the Labyrinthuleae, 
while in the higher, stalked forms, there is a comparatively high 
degree of differentiation among the individuals. 
The characters of the Acrasieae, while they present certain resem¬ 
blances to those of the two preceding groups, are thus sufficient to 
distinguish them very clearly. Their vegetative period includes 
neither the swarm cell nor the plasmodium condition of the Myxo- 
mycetes, and no phenomenon which might be compared to the vege¬ 
tative net-plasmodium of the Labyrinthuleae, occurs in their develop¬ 
mental history. On the other hand, the aggregations in the 
Acrasieae commonly called pseudoplasmodia, which precede fructi¬ 
fication, are, at least in the higher members of the group, far more 
clearly defined than the corresponding phenomena in the other 
orders; while the various degrees of complication presented by the 
final fructifications combine certain meagre resemblances to the rest¬ 
ing stages of both the Labyrinthuleae and the Myxomycetes with 
other peculiarities found in neither of them. 
It should be noted that in the preceding summary, the term 
'pseudospore is used in conformity with the suggestion made in a 
previous paper (: 01), since a comparison of the resting individuals 
which occur in the so called fructifications has shown that the term 
spore cannot properly be applied to them in all cases. In the cop- 
rophilous genera Sappinia, Guttulinopsis, and Diplophrys, the indi¬ 
viduals, even in mature fructifications, are merely slightly contracted 
and encysted, secreting no definite wall. On the renewal of a state 
of activity, such resting individuals, therefore, gradually assume the 
form of the vegetative cell without casting off a spore wall of any 
kind. In order to distinguish these bodies as well from true spores 
which replace them in a majority of the genera, as from the transi¬ 
tory resting conditions of isolated vegetating myxamoebae which 
were first called microcysts ” by Cienkowsky, the term pseudospore 
is here employed. 
It will be noted, moreover, that in characterizing the Acrasieae, 
emphasis is laid on the fact, usually overlooked in accounts of these 
organisms, that the vegetative stage ends before the pseudoplasmo- 
dium condition begins. The pseudoplasmodium, therefore, is a 
phenomenon connected not with vegetation but with fructification, 
and is by no means homologous with the plasmodium of true Myxo¬ 
mycetes, nor is it comparable in the least to the vegetative net-plas- 
