ARCHER — ON " PALM0GLO2AN" ALG.E. 277 



Micrasterias rotata and M. denticulata (for instance) present themselves, 

 they maintain, at least so far as we know, their own ultimate charac- 

 ters ? With us here they are both about equally common in their own 

 localities. It is clear that the greater number of subdivisions of the 

 former, its larger middle lobe, its more acute teeth, its greater size, &c, 

 give it no advantage over the latter in the " struggle for life," 

 although both have the pi'eponderance in numbers (in whatever the ad- 

 vantage may consist) over certain other well-marked allied forms. I 

 think it seems to follow from Dr. Wallich's statement of his views, that 

 " natural selection" must in his opinion fall into the back ground so 

 far as these organisms are concerned ; for, according to him, characters 

 derived from parents, however seemingly inherent here, must at once 

 succumb to varying surrounding physical conditions. 



Dr. Wallich says that the onus probandi, as regards that side of the 

 question against which I contend, does not lie with those who think 

 with him ; but " that it is sufficient to show a fair number of cases (as, 

 for instance, in the genus Micrasterias) in which unquestionable inter- 

 change of those characters is to be met with, which by Ealfs and 

 others have been seized upon as indicative of a distinct origin." Dr. 

 Wallich will, I hope, excuse me if I still hold that such cases have not 

 yet been shown in the established species of Micrasterias ; and that those 

 " interchanges of characters" are founded upon assumption of what it 

 is presumed might be, rather than what is. I venture to hold still 

 that the interchange of characters between the various species of Mi- 

 crasterias (I do not, I need hardly say, restrict myself to that genus, 

 but rather mention it as an example) has yet to be demonstrated. I 

 venture likewise as yet to hold that the admission of some forms as 

 species, and others not less well marked as varieties, in this Family (I 

 do not now, of course, refer to Protophyta in general), is, on the whole, 

 altogether arbitrary ; and I, for one, cannot refuse to go the length 

 that Nature seems to me here to go, and admit as species all those ulti- 

 mate forms which seem to be constantly distinct, keeping their ulti- 

 mate characters to themselves ; and each of which, by its own idiosyn- 

 cracies, one can at a glance perceive is the very same identical plant 

 which, described or undescribed, one encounters more or less rarely or 

 frequently in its own suitable localities. 



It will thus be seen, while I venture very deferentially, and with 

 the highest respect, to differ on points in relation to some Proto- 

 phyta from Dr. Hicks and Dr. Wallich, that there are others on which 

 I cannot but agree as yet with both observers. Nor does it seem to me 

 that the views here put forward conflict with those I ventured to ex- 

 press in my paper read to the Society last Session, on an amoeboid state 

 of Stephanosphrera, as regards the perhaps in individual opinion de- 

 bateable, but as I still hold by no means actually convertible, lower forms 

 of animal and vegetable life. Because some organisms are not always 

 what they seem to be, inasmuch as in the course of their development 

 they may submit themselves to several apparently more or less diver- 



