( 15' ) 



förmig aus, sie lassen sich vergleicheu init eiucm eingedrückten 

 Gummiball, sie alineln dom Hut eines Pilzes und durch die ein- 

 gedrüekte Stelle sielit man deutlich den Kern hindurchscliiramern." 



From the figure I think I may conclude that we can here have 

 to do with hardly anything else than with chromocratcrs, at least 

 with colls which have a great many properties in common with 

 those we have described. 



ElsiG in his Monographic dcr CapitelUden has figured at least 

 dish-shaped red bloodcells in Chaetopod worms (Notomastus). Nor 

 should wo omit to mention the figures and communications of 

 CuÉNOT) 1) concerning Cucumaria Planci, an Echinoderm, and of 

 Sipunculus and Phascalosoma (Gephyreans). 



That the same very characteristic species of cell, possessing a shape, 

 the appropriateness of which is at least very questionable, the sig- 

 nificance enigmatic (unless the calyxiform bloodcells of the Gephyreans 

 be congenial with chromocratcrs) should occur among such widely 

 divergent groups of animals as Pycnogonids, Petromyzontes, Molluscs 

 (perhaps) and Mammalia, justifies, in my opinion the conclusion, that 

 the chromocrater is a heritage from the common ancestors of the above 

 mentioned groups of animals, that is from worms. In the ontogenesis 

 of the red blood-corpuscles of mammalia the ancestral calyxiform 

 nucleated blood-cell again appears for a short duration. 



This investigation was carried on in the Physiological Laboratory 

 of Leyden and at the zoological station at tiie Helder. 



By the communications of Giglio Tos -) our attention was 

 directed to the Lamprey. 



Astronomy. — „Some remarks upon the Xi-monthhj motion of the 

 Pole of the Earth and upon the length of its period^'. By 

 Dr. E. F. VAX DE Sande Bakhuyzen (Comnmnicatod by 

 Prof. H. G. VAN DE Sande Bakhuyzen). 



(Will bo published in the Proceedings of the next meeting.) 



1) CuÉNOT, Etudes sur le sang etc. Arch. d. Zool. expcriraentale et générale. 

 IX. 1891. 



-) E. GlGLlo Tos, Sulle cellule del saiigue della lampreda. Accad. r^^ale della scienze 

 di Torino. 1896. 



