ROYAL MICROSCOPICAL CLUB. 191 



Ph.D., F.E.S.; *Sir John Lubbock, Bart., M.P., F.E.S. ; John 

 Millar, F.L.S. 



Treasurer — *J. W. Stephenson, F.R.A.S. 



Secretaries — H. J, Slack, P.G.S., and Jabez Hogg. 



Council — R. Braithwaite, M.D., P.L.S. ; J. Berney ; Charles 

 Brooke, M.A., F.E.S. ; *T. W. Burr, F.E.A.S. ; W. J. Gray, 

 M.D. ; Henry Lawson, M.D. ; Henry Lee, F.L.S., F.G.S. ; *S. 

 J. M'Intire ; *H. Perigal, F.E.A.S. ; G. W. Eoyston Pigott, 

 M.A., M.D. ; C. Stewart, F.L.S. ; T. C. White. (Those marked 

 with an asterisk being new names.) ' 



The following gentlemen were elected Fellows of the Society : 

 — Charles Gibson, Esq. ; David Johnson, Esq. ; William Boyd 

 Moss, M.D. 



March Qth, 1872. 



The President in the chair, 



A communication was read from Dr. J. J. Woodward (U.S.), 

 accompanying some micro-photographs. Dr. AYoodward praised 

 highly an immersion ygth objective of Messrs. Smith and Beck. 



Mr. Stephenson made some remarks on a new development of 

 his binocular arrangement for the microscope. The chief pecu- 

 liarity of the new arrangement was that the prisms were sc 

 reduced in size as to be inserted into the object-glass itself, and 

 their angle reduced from 7o° to 66"30°. It' had the great advan- 

 tage of being applicable to powers at least as high as ith of an 

 inch. 



Dr. Klein then read a paper on the development of the ovum 

 of the trout (Salmo fario). According to the observations of 

 Eusconi, who first investigated this subject, and of Prevost and 

 Dumas (1824), who studied Batrachia, the first step in develop- 

 ment consists in the division of the blastoderm into two parts, 

 each of which again divides into two ; i.e. the whole being then 

 marked by two grooves at right angles to one another, so as to 

 produce a cross, the segmental cross {furchungs kreuz), Coste 

 and others observed the same process in other Teleostea. Strieker's 

 results diifered somewhat from these, but were obtained by an 

 entirely different method, namely, by making sections. It was 

 objected to this method that the appearances produced might be 

 artificial, and not really belonging to the object, for which reason 

 Klein preferred to study the early stages in the living state. His 

 observations were in perfect accordance with those of Eusconi, 

 Coste, &c., on the points in which they are opposed to those of 

 Strieker. A detailed account was then given of the changes suc- 

 cessively observed in the ovum from day to day. The " cross," 

 showing the division of the blastoderm into four parts, was 

 observed in most ova at the end of the first day ; after thirty-six 

 hours, two of these quadrants were seen to be divided, and at the 

 end of the second day all the quadrants. After this time no 

 regularity was observed in the process of segmentation ; and on 

 the third day the whole blastoderm was covered with irregular 



