82 



K. KISHINOUYE. 



(3) The yolk nucleus is found in segmenting eggs on to the 

 four-cell stnoe. 



(4) After the segmentation all the nuclei are found only at 

 tlic surface of the egg, and none of them remain in (he volk. 



(5) The primary blastodermic' thickening may he considered 

 as a modified gastrean mouth, the formation of whir-h was obstructed 

 by the abundance of yolk. 



(6) The secondary blastodermic thickening or 'primitive 

 cumulus ' of Claparede plays a secondary part in the formation of the 

 germi n al 1 ay er s . 



(7) The brain and the ventral nerve cords are formed as a 

 continuous ectodermic thickening. 



(8) All the appendages are postoral in origin. 



(9) The first abdominal segment bears no appendages. 



(10) The large fat cells are derived from the endoderm. They 

 ff^rni blood corpuscles. 



(1 1) Ati invagination at the posterior l)ase of the first abdominrd 

 appendage gives rise to the lung-book. A similar invagination at the 

 base of the second gives I'ise to a tube — abortive trachea. 



(12) The unpaired cœlomic cavity, belonging to the anal lobe, 

 changes to the so-called stercoral pocket. Prolwbly it is excretory 

 in function, not a part of the alimentary canal. 



(13) The dorsal circulatory vessel is formed by the fusion of 

 the mesoblastic somites at the dorsal median line. 



(14) The so-called body cavity of the adult animal is not the 

 descendant of the cœlomic cavity, but it is a secondarily formed 



space. 



(15) The brain is composed of the semicircular grooves and the 

 lateral vesicles cut off from the ectoderm. Later it is divided into 

 three segments. 



