THE EMBRYOLOGY OF LIMULUS. 



J. S. KINGSLEY. 



CONTENTS. 



Historical 35 



Habits, etc 3° 



Methods 3° 



Ovigenesis 4° 



Early Development 4i 



Blastoderm Cuticle 47 



External Development 47 



Mesoderm 4° 



Development of External Form 49 



Comparisons • 53 



Historical. 



The embryology of Limulus has already given rise to con- 

 siderable literature, but there still remain many problems to be 

 solved. The first to describe any embryonic stage of this genift 

 was Henri Milne-Edwards, who figured and briefly described 

 ('38, '39, '40) a single larval stage. The next was Samuel Lock- 

 wood ('70), who gave an account of the oviposition, and the 

 hatching of the egg, and described several of the larval stages. 

 A. S. Packard followed with a long series of articles ('70 ^ '70 ^ 

 '70 ^ '71, '72, '73, '75, '80, '85), each of which added something to 

 our knowledge. Dohrn ('71), who studied material supplied 

 by Packard, was able to see some points which had escaped the 

 latter. Alexander Agassiz ('78) described the habits of the 

 young after the beginning of a free life, and contributed a figure 

 of the larva to Faxon's ('82) compilation of drawings illustrative 

 of the embryonic stages of Crustacea. The present writer made 

 his first contribution to our knowledge of the development of 

 Limulus in 1884, following it in October of the next year with a 

 more extended paper ('85). In the same month H. L. Osborn 

 ('85) and Brooks and Bruce ('85) published preliminary accounts 

 of their investigations ; the complete papers have not yet 



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