102 THE ROYAL SOCIETY OF CANADA 
EXPLANATION OF FIGURES. 
These figures are drawn to show diagrammatically the order in which the 
radial canals are developed in Æquorea. The introduction of the new canals is made 
more pronounced by not making any allowance for a difference in size of the medusa. 
There is one figure for each of the definite stages to the end of the fifth series. 
The perradials are numbered 1, the interradials 2, the primary adradials 3, the 
first eight of the fourth series 4a, the second eight 4b, the first eight of theffifth 
series 5a, the second eight 5b, the remaining sixteen 5c. 
Fig. 1 shows the 4 perradials. 
Fig. 2 shows figure 1 with 4 interradials added. 
Fig. 3 shows figure 2 with 8 primary adradials added. 
Fig. 4 shows figure 3 with the first 8 of the fourth series added. 
Fig. 5 shows figure 4 with the second 8 of the fourth series added. 
Fig. 6 shows figure 5 with the first 8 of the fifth series added. 
Fig. 7 shows figure 6 with the second 8 of the fifth series added. 
Fig. 8 shows figure 7 with the remainder of the fifth series added. 
