( 155 ) 



however do indeed remind lis of the thorn-apple shapes of the red 

 blood-corpuscles of mammalia and amphibia. 



The nucleus is ellipsoid. It lies in the proximity of the aboral 

 invagination, and appears to be connected here with the boundary 

 layer of the body of the cell by means of the microcentrum, the 

 group of centrosomes. 



The retraction sometimes tapers oft' rather sharply. The bottom 

 of the deep oral invagination also appears to be connected, thougli 

 much more loosely, with tlie nucleus. 



Under injurious influences the mouth may disappear and the cell 

 become globular, or tlie bottom of the oral invagination be thrust 

 outwards like a bag turned inside out, so tliat a (clear) vesicle is 

 extruded from the oral ring, or tlie tiiiclciis may he ejected from 

 the opening of the mouth. In preparations where the boundary layer 

 of the body of the cell presents itself as a sharply defined mem- 

 brane, a ring is visible round the mouth, viz. the oral ring. Round 

 the aboral invagination we observe in such preparations, thougli 

 less frequently, an aboral ring. What kind of pcriplieral, oral and 

 aboral differentiations, preformed in the living cell, lie at the bases 

 of these images, we cannot as yet say. 



These cells may be called ehromocraters, a word derived, by 

 analogy witli the term chromoeyt in zoology, from the Greek xo/'n^o, 

 a cup. 



The desirability of proposing this new name arises from the 

 circumstances that the chromocratere proves to be a red blood-corp- 

 uscle occurring in widely divergent groups of animals. It may 

 be a thing of importance in phylogeny and in mammalia an inheritance 

 of great antiquity. 



The co>iimo)i red blood-corpuscles of mammalia (rat^ cavia, rabbit) 

 pass through a stage, in which they are nucleated ehromocraters, 

 and that as mature erythroblasts or normoblasts, when the nucleus 

 is already pycnotically degenerated, n:hich cells eject their nucleus 

 through the oral invagination. 



They then become cup-shaped erythrocytodes (known already to 

 KiNDFLEiscH 1) and Howell-)): e.g. enucleated ehromocraters with 

 deep oral and less deep aboral invaginations. 



In the full-grown red blood-corpuscles of man viz. in the tips of 



') EixDFLEiscH, Ueb. Kuocheuraurk uiuL Bliitbildung. Areliiv t'. luikrosk. Anato- 

 mie. XVII. 1880. 



^) II'OWELL, The life liistory of the formed elements of tl\c blond, esppciidly the 

 red bloodcorpuscles; Jourual of Morphology. IV. 189U. 



