184 



BULLETIN OF THE 



(Figs. ^6, 57) is not yet as large as the right, and it consists of fewer 

 cells. 



The position of the connective between the visceral and pleural gan- 

 glia (Plate V. Fig. G3) is indicated by the presence of spindle-shaped 

 cells with fibrous projections. The connective is at this time long, and 

 the cells and fibres composing it are only joined to one another loosely. 



As the abdominal ganglion increases in size, it extends more toward 

 the right side of the body (Plate V. Fig. 61), and the connective be- 



PlGURE R. — The loft face of a section parallel to the sagittal plane finm an embryo of the 



eleventh day. X 73. 



ab. -vsc. s. Left abdominal-visceral connective. j)d. Tedal ganglion. 



ceb, s. Left rerebral ganglion. jie.^. Font. 



cnch. Shell gland. sac. rid. Railula sac. 



cy. Otocyst. la. Ocular tentacle. 



tween it and the right visceral ganglion, which is hardly perceptible at 

 this stage, is much shorter than that to the left visceral ganglion. 



The buccal ganglia remain in the same condition as in the preceding 

 stage (Plate 11. Fig. 22). 



By the eleventh day the embryo has increased greatly in size (Figure B) ; 

 the tentacles are prominent, and the pulsating sac of the foot is very 

 large. A narrow slit-like infolding of the ectoderm (compare Plate VIII. 

 Fig. 101, gl. pd.) has arisen in the median plane of the body at the an- 

 terior end of the foot, into which it extends backward a short distance. 

 It is the beginning of the foot gland. The salivary glands also make 



