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Ijhoren," ' Zeit. f. wiss. Zool.,' Bd. Ixxxvi, 1907. 



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EXPLANATION OF PLATES 42 and 43, 



Illustrating Mr. C. L. Boulenger's memoir '' On the Origin 

 and Migration of the Stinging-cells in Craspedote 

 Medusas." 



PLATE 42. 



Explanation of Lettering. 



ect. Ectoderm of the manubriimi. end. Endoderm of the manubrium. 

 gl.c. Gland-cell. nem. Endodermal nematocyst. nem} Nematocyst of 

 the oral battery. nem" and nem? Migrating nematocysts. s.l. 

 Structureless lamella, test. Testis. 



Fig. 1. — A longitudinal section of the proximal part of the manubrium 

 of the medusa, Moerisia lyonsi, to show the nematocysts in the 

 endoderm. 



