592 The American Naturalist. [July, 
investigation which is destined to reveal a rich harvest to any 
one who may take up the study of these facinating animals. 
There is no subject which would more richly repay observation 
than that of the Medusae of California. I have here pointed out 
the most important general structural features of these genera, 
and have introduced a few comparisons with similar genera 
from the Atlantic, with which students of zo51ogy are more 
Of the group called Acraspeda, or Discophorous Medusae, a 
species of Pelagia is one of the largest and most striking of those 
which make their way into the Santa Barbara Channel. Com- 
pared with the Pelagia of the Atlantic and Mediterranean Sea, 
Pelagia noctiluca, the Pacific Ocean representative, P. panopyra, 
is a veritable giant. Specimens were captured which had the 
" tentacles " of the mouth over four feet in length, and the 
dimensions of the body in proportion. The Atlantic Ocean 
Pelagia is commonly not more than a fifth of the size of this 
The first figure gives a representation of the general form of 
this Pelagia as it was observed floating near the surface of the 
water in mid-channel. The umbrella, which forms the upper 
portion or body, is over two feet in diameter, and from the center 
of the under side there hang down four long, frilled, flexible 
tentacles, which form the lips of the mouth, or oral aperture. 
There are eight "sense-bodies" arranged at regular intervals 
around the margin of the umbrella, alternately with which arise 
the tentacles, or the long, thread-like structures conspicuously 
shown in the figure. This Medusa, from its very large size, is 
one of the most striking, and seems to be common at certain 
seasons of the year, according to reports given to me by the fish- 
ermen, but I was able to collect only a half dozen good speci- 
mens. The examples captured had a beautiful pink color, which 
was especially brilliant on the tentacles and exterior of the 
umbrella. 
The genus of Acraspeda called Aurelia, represented on the 
Atlantic coast by the well-known A. flavidula, is also found in 
the Pacific, and is represented on the coast of California 
