E. MABSHALLI. — REPEOPUCTIVE ELEMEXTS. 189 



formation probably rests upon a mistaken interpretation of a 

 process of oogenesis. 



So far as concerns tlie arclueocyte-cougeries of tlie Hexacti- 

 nellida, I can confidently state that among the constituent cells 

 in any stage of its growth, there exists not one which, on ac- 

 count of its size or of other external 2>eculiarities, can be recognized 

 as an egg. If it be that so many cells are aggregated for the 

 sake of the nutrition of a developing ovum, this ovum is to be 

 expected to deviate more or less morphologically from the rest 

 as it approaches maturity; however, no sign of such a differen- 

 tiation is noticeable. Farther, all the cells in a congeries, large 

 or small, are tolerably uniformly and compactly packed together, 

 so as to directly touch one another ; and where they are some- 

 what loosely arranged, there is not a trace of any substance 

 between them. So that, I am decidedly against the assumption 

 that some of them are, at any stage of the growth of the con- 

 geries, engulfed among certain others as pabulum. If, after all 

 that, a portion or all of the cells in a congeries giving rise to 

 an embryo are still to be looked at in the light of blastoraeres 

 lliat have arisen by segmentation from a single egg-cell, one is 

 driven to the assumption that the original ovum is, like the 

 blastomeres themselves, as small-bodied as, and indistinguishable 

 from, an archffiocyte. This would be very remarkable in an 

 ovum ; and moreover, under that supposition, it become impera- 

 tive to deny egg-nature to the large ovum-like cells described by 

 ScHULZE and by myself from Evpledella. 



It is idle to go into further speculations. From all that I 

 have seen, I am inclined at present to entertain views similar 

 to those put forward by H. V. Wilson in attempting to explain 

 the nature and origin of the larvie I have discovered in the 



