S. W.Ford — Note on ma. 141 



extraordinary industry of bees and the number of flowers 



which pollen is sometimes transported, is far greater than one 

 would have supposed. But the volume is reprinting by the 

 Appletons, and will soon be within the reach of all,— along 

 with a new edition of the orchid-fertilization book, the proper 

 supplement to the present work, relating as it does to the 

 class of plants in which the adaptation for fertilization by 

 insects is carried to the highest degree of specialization and 

 perfection. 



Art. XVII.— Note on Microdiscm speciosus ; by S. W. Ford. 



In my original description of this interesting Trilobite (this 

 Journal* August, 1873) it is stated that the thorax is composed 

 of four equal segments. The description, in so far as relates to 

 this part of the animal organization, was drawn up from the 

 study of a single specimen, showing the head, thorax and 

 pygidium in nearly their natural positions, and apparently offer- 

 ing decisive testimony as to the true number ot body-rings. 

 Somewhat more than a year ago, however, I obtained from the 

 Troy beds another specimen, of almost precisely the same 

 dimensions, showing clearly but three segments in the thorax; 

 and, subsequently, a much larger specimen showing the same 

 number. This led me to re-exam in u < i lly, the speci- 



men emplo . - | fcion, when it was found 



that the head ha I si 1. and that what I had 



regarded as the first pleura (all of the pleura) of one side, as 

 well as one-half of the'; | i" the matrix) was 



a fragment of some foreign bodv that had fallen into the gap 

 thus made The deception, in the first instance, was rendered 

 all the more complete from the fact that, b\ th< displ ceim it 

 of the head | safer fold rf the ftrsl • 



which is or: ; n from view by the backward 



prolongation of the glabella, was exposed, thus making a very 

 good case for a fourth segment. I now Cottt 

 this species has never more than three body-rings. I have in 

 my collection i sm 1 rolled i .-extremi- 



ties of but two body-segments, and I was at first led to think it 

 possible that we had in this species an example of the meta- 

 morphoses of Trilobites, concerning which Barrande has taught 

 us so much. But as I have observed since this speeimei was 

 obtained, an individual of even smaller size, with three per- 



' "'■:.' ■:■■ :...!•.,;.-. •- ; - - - ' ' 



at the present time. I should here also add that the last body- 



