40 



THE DEVELOPMENT OF 



'84, Urbanowicz, Felix. Zur Entwicklungsgeschichte der Cyclopiden. 



Zool. Anz., vil, pp. 615-619. 1884. 

 '78, Whitman, C. 0. The Embryology of Clepsine. Quarterly Jour. 



Micros. Sci., xvm, pis. xn-xv. July, 1878. 

 '86 (Whitman, C. O.). The germ layers of Clepsine. Zool. Anz., ix, 



pp. 171-176, 1886. 

 '87, A contribution to the history of the germ-layers in Clepsine. 



Jour. Morphol., i, 105-182, pis. iv-vi. 1887. 

 '87, Wilson, E. B. The germ-bands of Lumbricus. Journ. Morphol. 



I, pp. 183-192, pi. viz. 1887. 



EXPLANATION OF PLATES I, II AND III. 



The numbering of the figures is consecutive with that of the pre- 

 ceding part (Vol. xvin, pis. i and n). 



REFERENCE LETTERS. 



a abdomen. 



af abdominal flexure. 



an anus. 



ap appendage. 



be body cavity. 



bg boundary between optic 

 and cerebral ganglia. 



bl blastopore. 



c cerebral ganglion. 



cc crystalline cone. 



c/i chorion. 



cl corneal lens. 



cm commissure or commis- 

 sural fibres. 



co body cavity. 



ct cuticle. 



cv connective or connective 

 fibres. 



d dorsal vessel. 



dm dorsal mesoderm. 



do dorsal organ. 



e ectoderm. 



ec edge of carapax. 



eo external opening of green 

 gland. 



ex extensor muscles of ab- 

 domen. 



ey eye. 



/ flexor muscles of abdo- 

 men. 



fc fibres of cerebral gang- 

 lion. 



fo fibres of optic ganglion. 



g (1-17) ganglia of the primi- 

 tively postoral series. 



ga germinal area. 



gc germinal cells. 



gg green gland. 



gm stomach. 



gt gastric teeth. 



h entoderm. 



ht heart. 



i-xx appendages. 



i intestine. 



I labrum. 



li " liver." 



m mesoderm (mouth in fig. 

 11). 



me mesentery. 



gm mesoderm of green 

 gland. 



mn mandibular nerve. 



mo mouth. 



mu muscle. 



