1894. | NEW YORK ACADEMY OF SCIENCES. 135 
made the subject of remark. Indeed, up to the middle Cre- 
taceous we find the recurrence of much the same forms in Green- 
land, in Central North America, along our Atlantic seaboard 
and in Western Europe. As I have elsewhere maintained, it 
appears to me that in this wide early diffusion of similar or 
identical organisms we have a more philosophical basis for the 
explanation of occurrences, such as above cited, than in the 
widely accepted hypothesis that any given species has origi- 
nated in a limited area, and thence “ migrated.” And if my 
position in this is tenable it has an important bearing on the 
subject in hand. 
I have confined my remarks to the consideration of present- 
existing plants. If we find the “species problem” so intricate 
in these, how much more difficult must it be in the study of 
fossils? For in these, if our modern pet theory be trne, we will 
sooner or later accumulate material which will invalidate all 
paleontological ‘ species.” The “lines of descent” already 
worked out foreshadow this result very clearly. What then 
shall we do with these organisms? It is necessary to recognize 
them as autonomous in order to study them at all, and in order 
to study them to any advantage we have to apply to them desig- 
nations of some kind. It appears as though our present 
methods of nomenclature would prove insufficient to meet the 
necessities of this new biological era, so rapidly opening before 
us, but what will be substituted for them is not yet clear. Itis 
to be hoped that when another method comes into vogue it will 
be so constituted as to be applicable to all organisms both past 
aud present. 
On the History of the Archoplasm Mass in the Sperma- 
togenesis of Lumbricus. 
By Gary. N. CALKINS. 
The history of the reproductive cells in Lumbricus offers 
many interesting and perhaps some unique problems. Of these 
probably the most striking is that which relates to the origin 
and fate of a body which acts like an attraction center in the 
early germ cells, and which finally becomes the middle piece of 
the mature spermatozoan. This body, which appears in diverse 
forms in the different stages of sexual development of Lum- 
bricus, may be called the archoplasm mass. 
The archoplasm mass in some cases is elongated and flattened 
and lies closely applied to the exterior of the nuclear membrane. 
