224 



CHAS. W. HARGITT. 



for a time an internal nuclear proliferation, followed later by the 

 spontaneous division of the cytoplasm into a corresponding num- 

 ber of blastomeres. While my own observations (op, cif.} did 

 not fully confirm those of Brauer they abundantly proved the 

 general proposition that cleavage is not uniform, either in mode or 

 progress. The work of Allen (op. cit.} showed even more con- 

 clusively the variation of this feature in T. crocea. 



The same thing is true in the eggs of C. leptostyla. While 

 there is here much more uniformity than in either of the former 

 cases the range of variation is still very considerable, as a glance 

 at the various figures will abundantly show. 



FIGS. 3, 4, 5. Camera sketches of phases of cleavage, from life. 



The account of Harm (op. cit., p. 28) concerning cleavage in 

 C. squainata is in very marked contrast in its general aspects. 

 Both in his descriptions and figures there is a most striking regu- 

 larity and definiteness in the cleavage. He very briefly refers to 

 a condition which he considers exceptional and abnormal, but 

 which unless I greatly mistake must.be much more common than 

 he is disposed to think. It is quite similar to a condition referred 

 to by Brauer, and regarded by him as likewise exceptional, but 

 which I have showed to be more or less common. 



Again, Harm describes in some detail what he regards as a 

 more or less definite rotation of the blastomeres during earlier 



o 



cleavage, in some measure comparable with phenomena familiar 

 in the eggs of annelids and molluscs. When attention is directed 

 to the fact that in these hydroids the eggs are usually quite 

 closely confined within the closed walls of the gonophore, and 

 that, whether there be two or even more in a single gonad, they 

 are always more or less flattened against each other or against 



