250 EDWARD T. BROWNE. 



tentaculocysts. Their absence is probably due to the exami- 

 nation of an insufficient number of specimens. 



A variation in the number of tentaculocysts does not inter- 

 fere with the other organs of the body. There appears to be 

 a correlated variation between the number of genital pouches 

 and buccal arms, and eight specimens show it. 



One specimen has three genital pouches, three buccal arms, 

 and nine tentaculocysts. 



Three specimens have three genital pouches, three buccal 

 arms, and each one has traces of a fourth genital pouch and a 

 fourth arm. Two have eight tentaculocysts, and the other has 

 ten tentaculocysts. 



One specimen has five genital pouches, five buccal arms, and 

 eight tentaculocysts. 



Three specimens have six genital pouches, six buccal 

 arms ; two have eleven tentaculocysts, and one has twelve 

 tentaculocysts. 



I have not given drawings of these specimens, as somewhat 

 similar forms have already been figured by Elirenberg (1) 

 and Romanes (2). Mr. Bateson, in his recent book, 'Mate- 

 rials for the Study of Variation,' gives abstracts and figures 

 from the papers of Ehreuberg and Romanes. He also gives 

 a table which shows that 26 specimens (1'49 per cent.) out of 

 1763 adult Aurelia, washed ashore on the Northumberland 

 coast in 1892, have more or less than four genital pouches. 

 The Plymouth specimens show 2*08 per cent, with an abnormal 

 number of genital pouches. 



It may be difficult to notice in a few years what effect the 

 numerical variability of the tentaculocysts has upon the adult 

 Aurelia. The variation shows a tendency for an increase of 

 the tentaculocysts, since the specimens displaying an increase 

 are about three times as numerous as those possessing a 

 diminished number. Whether this will change the present 

 characteristic features of the species or not can only be found 

 out by examining the ephyraj and adults at long intervals of 

 time, and comparing the results with previous records. 



