HARDWICKE'S SCIENCE-GOSSIP. 



155 



conditions, makes the horse-chestnut tree assume a 

 tolerably symmetrical shape. 



There are, however, plants mostly herbaceous, in 

 which the buds in the axils of opposite leaves do not 

 grow equally, that on one side being alone developed 

 or growing much more rapidly than its opposite 

 neighbour. Plants of the order Caryophyllacea? often 

 display this character, along with an alternation of the 

 sides where vigorous branches grow. The leaves 

 being decussate, the branch in the axil of one of them 

 grows in a plane, at right angles with that of the one 

 immediately below it, and that next above it on the 

 opposite side. So then, though the leaves are 

 opposite, the branches growing on alternate sides 

 form a spire, including those axillary to four leaves, 

 the fifth being above the first. On the opposite sides 

 the leaf-buds are either undeveloped, or are much 

 more backward in their growth. The common weed 

 called cleavers {Galium Aparinc) also shows this 

 mode of branching very well. That of the whorl of 

 leaf-like organs which surround the stem of this 

 plant, only two contain buds in their axils, is an 

 argument in support of the position that only those 

 are true leaves and the others stipules. That the 

 leaf-bud on one side is always in advance of that on 

 the other side, and that in this they show a similarity 

 to our pinks and chickweeds, is a matter of additional 

 interest. 



RESEARCHES IN POND LIFE. 



No. II. 



REFERRING to my previous communication 

 respecting the Acineta, I have now a few 

 more interesting facts to state, being the result 

 of a series of careful observations, and I think 

 they throw some light on a few hitherto doubtful 

 points. I stated in my last paper that I believed 

 the perfect forms of Acineta, which were in such 

 large numbers upon the filaments of the Alga, 

 were developed from the rudimentary gelatinous 

 masses, or more properly, perhaps, we should call 

 them the Amoeboid form of Acineta as observed last 

 autumn. This, of course, it is impossible to state as a 

 fact, not having seen them so develop, but there is 

 very strong and reasonable ground to infer such 

 was the case, the Amoeboid forms having disappeared 

 and these swarms of perfect Acineta taking their place 

 on that identical Alga and that only. I stated also 

 that I believed the Acineta to be attached parasitically 

 as it were to the steins of the tree form of Epistylis 

 as there figured and that they formed no part of the 

 organism itself; that I think is clearly established 

 by the following observations. Upon watching a 

 large number of the Acineta, I found in several, an 

 egg-like body or zoospore developing in the interior 

 (see fig. S8 a). 



Keeping in view one in a forward condition, in a 



short time the ovule escaped and was furnished with 

 a ring of cilia round the centre (see fig. 88 b) by means 

 of which it rapidly whirls about for some few minutes ; 

 it then attached itself close to one of the clusters 

 of Epistylis cups, so numerous on the filament 

 of weed, and then commenced a most interesting 

 development. The ovule in half-an-hour after its at- 

 tachment had developed a short pedicle (see fig. 89 A), 

 and in two hours it had assumed the form represented 

 in the " Micrographic Dictionary," and named the 

 PodopJiyra fixa (see fig. 90). The description there 

 given is somewhat vague, but it is stated to be the 

 Podophyra stage of Yorticella, as I think erroneously, 

 for in the course of about two hours more it had 

 assumed the form of a perfect Acineta, the body 

 becoming triangular in form with the radiations pro- 

 jecting from the corners (see fig. 91), and those 

 projecting in its earlier stage from other parts of the 

 globular body being absorbed. 



This development was watched throughout, not in 

 one instance only, but in a great number of cases, 

 thus clearly showing that these perfect Acineta 

 forms develop others by means of these ovules or 

 zoospores and that they in this active ovoid form attach 

 themselves to other bodies, and doubtless in this way 

 became attached to the stems of the tree Epistyles, 

 Carchecium, &c, as represented in my former paper. 



Now, although these observations seemed very clear 

 and satisfactory, I still felt a doubt as to whether it 

 might not be possible to discover some connection 

 between the Acineta and the Vorticella, as there were 

 so many clusters of those of Epistylis cups, as well as 

 Vorticella ncbulifera, &c, attached to the Algoe. And 

 while watching the development of these Acineta 

 ovules on two occasions there came into view one or 

 two active ciliated ovules of a somewhat different 

 appearance, being much longer in form with the cilia 

 near to one end. In two instances they attached 

 themselves by the ciliated end to the glass cell, which 

 was a bad position for observing their development, 

 having to look end on. In a short time they seemed 

 to assume the form of an Epistylis cup, the cilia round 

 the base being gradually absorbed, a short pedicle 

 then developed and the free end eventually opened 

 with the cilia round the mouth of the cup. This 

 seemed so clearly the development of an Epistylis, 

 or Vorticella, that it made it most important to 

 discover where these long-shaped ovules came from, 

 and to get a more favourable view of their development. 

 Was it possible that they also were developed from 

 the Acineta ; that in fact the Acineta produced two 

 kinds of ovules, the one developing into Acineta, and 

 the other into an Epistylis or Vorticella ? 



By much searching, and many nights' watching, I 

 fortunately discovered their origin. After examining 

 a number of the filaments of the weed, I found one 

 piece with a large number of Vorticella nebulifera, 

 attached, and fortunately several of them were in 

 various stages of fission (see fig. 92), and it occurred 



