144 BULLETIN : iMUSEUM OF COMPARATIVE ZOOLOGY. 



ABBREVIATIONS. 



I 



For explanation of tlie letters and exponents designating blastoracrcs, see 

 explanation of tlie nomenclature of cleavage (pp. 74-70). 



ec'bl. Ectoblast. 



en'W. Entoblast. 



Ibr. Labrum. 



mb.vt. Vitelline membrane. 



md. Mandible. 



7ns'b/. Mesoblast of double origin. 



ms'bl'. " Secondary mesoblast " (ecto- 



blastic mesoblast). 



pr'nl. $ Male pronucleus. 



pr'nl. 9 Female pronucleus. 



The Roman numerals I. II. (Figs. 28, oO) indicate the position of the first and 

 second cleavage planes, respectively; the Arabic numerals 1-4 (Figs. Ul, 9o, ll*2- 

 12(3), the sequence in which the transverse furrows marking off tiie Nauplius 

 appendages make their appearance. 



Plate 7. Figs. 56-65. 



Plate 8. Figs. 6G-73. 



Plate 9. Figs. 74-86. 



Plate 10. Figs. 87-94. 



Plate 11. Figs. 05-110. 



Plate 12. Figs. 111-120. 



