22O CHAS. VV. HARG1TT. 



MATURATION. 



Concerning this phase of development there is comparatively 

 little to be said in the case of Clava. I have studied as critically 

 as the nature of the egg would allow the behavior involved in 

 maturation both in living and preserved material, and in a very 

 large number of preparations, but with almost wholly negative 

 results. That is, I have found the phenomena to be so obscured 

 by the opacity of the cytoplasm, or by the pigment matter in the 

 yolk, or as seems to me a still further probability, namely, the 

 extremely fugitive character of the phenomena, as to render them 

 indistinguishable. I have had occasion to emphasize this matter 

 in several earlier papers dealing with the subject. The observa- 

 tions made upon the eggs of Pennaria have been duplicated, 

 almost point by point in the present case. Of course, in the egg 

 of Clava there is the added di c'ulty that all the phenomena 

 occur within the closed gonophore. In sections, however, this 

 fact ought to offer no serious obstructions to their detection, yet 

 the results, as in the former, are quite as uncertain and in most 

 cases absolutely lacking. 



In the case of CLwa squainata, Harm (op. cit., p. 23) describes 

 the phenomena in some detail, and gives almost diagrammatic 

 drawings of the several stages. However, as will be further 

 shown in connection with the cleavage phases, there are so many 

 points of difference between these species that the ova may per- 

 haps belong to very different classes so far as their character and 

 texture are concerned. From the fact that in several particulars 

 I have been able to confirm the observations of Harm it does not 

 seem probable that they are so greatly different as might be im- 

 plied. 



I shall briefly describe the principal features which it has been 

 possible to certainly determine, leaving others open to further in- 

 quiry or study. 



As pointed out in an earlier section, about the time the ova 

 approach full size the nuclei are to be found close to the outer 

 periphery as will be seen in several of the accompanying photo- 

 graphs. It will also be observed that the eggs occupy closely 

 the entire space of the gonophore, and that, therefore, the nuclei 

 in coming in contact with the gonophore wall become more or 



