J. W. Fewkes—Medusa from New England. 124 
pair of compound lappets* and are separated by incisions in the 
bell-margin equal to that in the radii of the sense bodies. 
Hach large velar lappet is pointed at its free rim, thin and flex- 
ible. All velar lappets are penetrated by an anastomosing net- 
work of vessels, and are destitute of a marginal vessel skirting 
its rim. There are no tentacles. 
Deep grooves in the exumbral walls of the bell, extending 
radially from the incisions, both occular and velar, are supposed 
to be in part characteristic of the live animal and in part due 
to the state of preservation. These are indicated by indistinct 
lines in our figure. They may be wholly a result of contrac- 
tion of the bell margin.+ 
The distance between two sense bodies on the margin of the 
extended bell of a fragment is 105™™. The tliickness of the 
umbrella increase very greatly at the junction of the marginal 
lappets. 
The lower surface of the umbrella (subumbrella) is divided 
into two regions, a central from which hangs the oral append- 
ages and a peripheral. The peripheral region is occupied by 
sections of muscular fibers forming together a strong circular 
compound muscle. There are sixteen sectors in this compound 
muscle. The radii passing to the sense bodies and those to the 
incision which separates the two larger velar lappets of each 
octant of the bell-margin also indicate the line of separation of 
the compound muscle. Hach sector of muscle is composed of 
a number of parallel folds extending from the radii mentioned 
and from a line near the union of the oral arms to a line con- 
necting the occular and large median velar incision. The 
breadth{ of the sector of muscle is 80™. In alcohol the 
muscle has a brown color; along the occular radii and that 
which passes through the large velar incision this color is 
absent. 
The size and arrangement of these muscles recall that of the 
subumbral muscle of Stomolophus, and somewhat more dis- 
tantly the same in Crambessa Tagi, as figured by Grenacher 
and Noll (op. cit. pl. iv, fig. vil, m), where, however, in the 
latter case the number of sectors appears greater. The promi- 
nence of the muscle on the under floor or subumbrella of Necto- 
pulema is apparently very different from Ahizostoma luteum of 
the last mentioned authors, if pl. vill, fig. xvu (op. cvt.), cor- 
rectly represents the subumbrella of A. dutewm Gren. and Noll. 
* My nomenclature “compound lappets”’ will lead to no confusion if the reader 
remembers that two small lappets (velar) unite to form the compound axial 
region at the base of these lappets. The compound lappets adjoin the occular 
lappets (see figure). 
+ These furrows recall the radial furrows of the umbrella border of Polyrhiza 
Heeck. 
t Distance from axial to abaxial border. Measurements of specimens of 
meduse preserved in alcohol, are more or less deceptive. 
