12 
Since the above was put in type I have made 
a seventh stop for oblique illumination, and which 
»¢ produces such excellent results with the condenser 
that I likewise had an engraving made of it. 
This stop works well with the jth. 
The Wistotocy of the Repropuctive Oreans of the Irip, 
TiGRIDIA CONCHIFLORA ; with a DESCRIPTION Of the Puz- 
NomENA of its Imprecnation. By P. Marrin Duncan, 
M.B. Lond., Sec. Geol. Soc., &c. 
ConrtTENTS. 
I.—IJntroduction. 
I1.— General description of the anatomy and development 
of the ovule. 
IlI.—The pollen-tube, its origin, growth, cellularity, func- 
tion, and decadence. 
IV.—The changes in the ovule consequent upon impregnation. 
V.—Remarks. 
I.—Some years ago, when the great German structural 
botanists were investigating, and not with their usual calmness, 
the phenomena of the development of the embryo in flower- 
ing plants, I was led to follow in their path of research. In- 
stead of examining the complicated phenomena of the impreg- 
nation of Dicotyledonous ovules, I laboured amongst Mono- 
cotyledons ; and the following history of ovular development, 
of the growth and function of the pollen-tube, and of the 
impregnation of the embryo-sac, may be taken as a fair 
Son of part of the philosophy of reproduction in that 
class. 
The abstract of the original paper, which was read at the 
British Association, and published in the ‘ Transactions,’ gave 
a fair analysis of the new matter. Since then the notion 
that the embryo was formed out of the end of the pollen-tube 
has been proved to be fallacious by its once very resolute 
supporters. It is a matter of satisfaction that the ideas of 
English botanists have passed safely through the ordeal, and 
that time has proved the correctness of the following obser- 
vations. 
The Tigridia conchiflora was chosen for the following 
reasons : 
