154 THE AMERICAN MONTHLY [Sept 



The Egg. — An egg (fig-. M) is a primordial cell set 

 aside for reproduction. While developing, the nucleus- 

 in the yolk separates just as in the case of the amoeba,' • 

 (fig. N). The two cells then form four (lig.vO) and the- 

 four form eight (fig. S) and so on untiL.the .entire- .YO;lk,. is 

 occupied and there arise three distinct layers .called, 

 epiblast (fig, T, c.) hypoblast, , d, and the mesoblg,st,, e.> 

 Upon these, as fundamental principles, -all animal: Bj;id" 

 vegetabl-e structure is built. -, -,^.,.^ 



Micro-Studies inUarine Z^lo|y:r^^ 



- — ' _:-/c^"r-'a . 



Bv James H6rnbi.i-/Jers^v7'I>js--©^\ •■';,' ■'.:.-: 

 A new series will-be at onc^JDegufci>^(;nd." qpnsiderably 

 improved. The slides win;43jJj:^crea^e4H:fi^nfiikhe.,r_^^ 

 an increase, :^of six^"e^ch of the-f6ur fhembtrs of the magti;- 

 zine will range from '28 to 32 pages or m:ore. The, plates 

 will number three /or four in each h^mbef; A new 

 feature will be the^-introduction ^f__numer-€ra:s:;fi-^5^^ in 

 the text. Tlie-^a,dj.cal feature of' iaip^ovem&n-t-.will be 

 however, that all the text will relate toJ.he slides and the 

 plates. There will he no miscellaneous articlesr'^Each 

 instalment of slides and its corresponding numb'gTs will 

 be confined to jTsingle class or phj^luni^^s the -.case may 

 be, and hence the"issue will be on systematic lines. 



The Third Series will treat of the Protozoa, Sponge's',' 

 Hydrozoa, ^"•nd Actinozoa— one instalment to each. There'' 

 will be no danger of duplication of slides already in" 

 Subscribers' cabinets, as the author will issue with 'each'-' 

 number a list of slides proposed to bfe sent, •togetllhei'' ' 

 with an alternative list from which substituted may' be'^ 

 selected for such as may not be desired in the othei^ list'.^ 

 The number to 'beiss'ued ¥rSt'' will ' deal with f fie 

 Sponges, and will c6mprisfe^ sOm^^U^^^ preparatidn's. 



Special attention will be takeii in the' ringing" of the 

 slides to secure permanency. 



