palial tentacles on their under sides. We have, then, at 

 this stage the mai'ginal zone of the umbrella marked by a nim- 

 ber of short radial ridges separated by an equal number of thin 

 areas. The ridges are in line with the radial canals. At 

 the principal end of each ridge the margin of the umbrella is 

 produced into two lobes, those adjoining the rhopalia (sli.l.) 

 being well marked, the others (i.l.) small and inconspicuous. 

 In Fig. 22 thei'e are twenty- three rhopalia. This is an 

 unusually large number and it will be noticed that the number 

 of marginal lobes has not increased in proportion, so that ir- 

 regularities of the margin occur in many places. Indeed I 

 think if a bifurcated rhopalium were added that this one spec- 

 imen would show all the irregularities of the margin that can 

 occur in this stage of existence in a Oassiopea. In 

 scyphistomas forked tentacles may occasionally be fourd, and 

 bifurcated rhopalia are not uncommon in the medusae. Between 

 the bifurcated rhopalium and two complete pt.rameres in the place 

 of one, we find all degrees of duplication: The first stage 

 beyond the double rhopalium is seen at 1. in Fig. 22, at 3. or 

 4. there is a greater separation, while at 5. we have two near- 

 ly complete parameres. Except for this multiplication of mar- 

 ginal parts the specimen is perfectly normal. 



52 - 



