46 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 
In the Pacific Cestum the lateral ends of the long body bear yellow 
pigment, according to the figure by Mertens, 1833, and the description 
and figure by Bigelow, 1904. This has not been observed in the Atlantic 
or Mediterranean Cestum, but it occurs in the closely allied Folia from 
Tortugas. The coloration may be due to the presence of commensal 
plant-cells. 
Genus FOLIA (nom. nov.) 
Vexillum, preoccupied by Botten for Mollusca in 1798. 
Vexillum, Fo, 1869, Anat. und Entwick. der Rippenquallen, Berlin, p. 6—Cuun, 
1880, Ctenophoren des Golfes von Neapel, pp. 300, 302. 
GENERIC CHARACTERS. 
Cestide with body elongated in the stomodeal axis, as in Cestum, 
but with the aboral narrow edge flat, not arched, as in Cestum. The 4 
subtentacular meridional tubes do not bend outward and inward from 
their points of origin from the 4 adradial vessels as in Cestum, but pro- 
ceed straight outward along the middle of the broad sides of the animal. 
The type species and only known form is Folia parallela of the Medi- 
terranean and tropical Atlantic. 
The genus is closely allied to Cestum, but is at once distinguished 
by its straight, subtentacular canals, whereas those of Cestum curve where 
they arise from the axial canal-system. 
Unfortunately we can not retain the generic name Vexillum, for 
it was preoccupied for Mollusca by Bolten, 1798, in Catalogus Museum 
Boltenanum, Pars Secunda, p. 138, and this name is accepted by Her- 
mannsen, 1847, in Indicis generum malacoz., vol. 2. I therefore propose 
the name Folia, in honor of Professor Fol, who discovered this cteno- 
phore among the Canary Islands. 
Folia parallela. (Figs. 62 to 65, plates 13 and 14.) 
Vexillum parallelum, Fou, 1869, Anat. und Entwick. der Rippenquallen, Berlin, 
p. 6, Taf. 2, Fign. 1-5 —Cuuwn, 1880, Ctenophoren des Ifes von Neapel, 
p. 303, Taf. 11, Fign. 4-6, Taf. 13, Fign. 14-17; 1898, Ctenophoren der Plank- 
ton-Expedition, p. 21.—MoseEr, 1908, Abhandl. ‘Akad. Minchen, Suppl. Bd. 
1, Abhandl. 4, p. 15. 
This species is smaller than Cestum veneris, being only about 15 mm. 
high and 150 mm. wide. The aboral edge is nearly flat, not arched as 
in Cestum. The stomodeum is shorter than in Cestum, being not half 
as long as the height (oral-aboral axis) of the animal. Above all the 4 
subtentacular meridional tubes proceed straight outward along the middle 
of the broad sides of the animal from their points of origin at the ends of 
the 4 rudimentary adradial canals to the edge of the outermost sides 
of the animal, where they join the 4 subventral canals. The separation 
between the subtentacular and subventral rows of combs is not so wide 
as in Cestum, being hardly perceptible in some specimens. The tentacle- 
bulb and its sheath are smaller than in Cestum. In the Mediterranean 
the Folia is colorless, but at Tortugas, Florida, some of the specimens 
(not all) show faint yellow in the gelatinous substance of the aboral 
sides of the extended ends of the animal. This yellow color may, how- 
ever, be due to the presence of commensal plant cells. Fol described 
this ctenophore from the Canary Islands, and Chun found it in the Medi- 
