370 CHARLES LL. BOULENGER. 
The remaining forty-four abnormal individuals had the 
typical number of radial canals and gonads, but possessed 
additional tentacles in various positions on the umbrella edge. 
In most cases these additional tentacles were so arranged as 
not to destroy the radial symmetry of the medusa; ten 
individuals had four inter-radial as well as the four per-radial 
tentacles, whilst as many as twenty-eight possessed, in 
addition, eight adradial ones, thus making a total of sixteen 
tentacles. 
The remaining six individuals were asymmetrical, the 
asymmetry being due to the development of an incomplete 
number of adradial and subradial tentacles. 
I have given below in tabular form a detailed account of 
the number and arrangement of the radial canals in the 400 
individuals examined. 
VARIATION IN THE MeEpUSA. 
Table Showing the Number and Arrangement of 
the Radial Canals and Tentacles in 400 Indi- 
viduals. 
Number of Tentacles. 
| Number of Number of ee ee ip Banc 
Individuals.| Radial Canals. ; 
Per-radial.| Inter-radial. | Adradial. | Subradial.| Total. 
1 3 3 = phe = 3 
345 4 4 — — — 4 
Ii 4 4 Il — — 5 
1 4 4, ay 2 — 7 
i + 4 — lo — 5 
2 4, 4 2 4, — 10 
10 4 4, 4 — = 8 
28 4 4, 4 8 — 16 
1 4: 4 4 8 6 22 
9 5 5 — — — 5 
1 6 6 _ — — 6 
Total 400 
It is a well-known fact that many medusge which in the 
adult condition possess a large number of tentacles commence 
