CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 39 
canals, there are numerous wart-like protuberances, under which lie 
diverticula of the canals. The lateral branches of the paragastric tubes 
give rise to complex windings near the inner sides of the auricles, and 
the meridional ventral tubes wind complexly in the oral lappets, forming 
complete circuits. The stomodzum is flat and its broad side is con- 
stricted near the middle. The axial funnel-tube is only about one- 
eighth as long as the stomodzum and the meridional canals are of fine 
caliber. There are no tentacles and no tentacular vessels. The animal 
is of a milky translucent hue, the wart-like protuberances on the oral 
lobes being milky-white in color. 
Young animal: When the broad, lateral diameter is 8.5 mm. 
(fig. 55, plate 10) the creature has assumed all the essential characters 
of the adult except that the meridional ventral canals give rise to a simple 
loop in the oral lobes and the lateral branches of the paragastric tubes 
lead straight into the auricles and do not wind on the way, as in the 
adult. There are neither tentacles nor tentacular canals. The auricles 
are mere short, flat protuberances. The meridional ventral rows of 
cilia consist of only 2 combs each, while the 4 auricular rows contain 3 
combs each. The simple capsule of the apical sense-organ lies upon the 
surface and is not sunken within a groove, as in the adult. A long, 
narrow pole-plate extends out on both sides of the sense-organ. At this 
stage the animal moves its oral lobes with great strength and agility 
and swims with considerable rapidity. 
When the Ocyropsis is 26 mm. in its broad, lateral diameter (fig. 56, 
plate 10) there are 11 to 12 combs of cilia in each subventral and the 
same number in each auricular row. The lateral, blind branches of the 
subventral canals in the lobes have appeared. The stomodzeum is 
beginning to be constricted in the middle as in the adult, and the canal- 
system begins to assume the characteristic windings. 
One often observes yellow or brownish-purple masses in the canals 
of this ctenophore, especially in the blind side branches from the merid- 
ional ventral vessels. These masses move about more or less in the 
currents of the canal-system and disappear after the animal has been 
captive, and unfed, in an aquarium for a day or two. I am inclined to 
regard them as products of digestion or of excretion. 
This ctenophore is capricious in its appearance, but in some years 
it is quite common at Tortugas, Florida, swimming in swarms near the 
surface in spring and early summer on calm days, and sinking when the 
sea becomes rippled. 
O. crystallina is widely distributed over the tropical Atlantic, and 
it is represented in the tropical Pacific by a closely allied variety with 
shorter auricles and longer oral lobes, which has recently been described 
by Bigelow, 1904, as O. pteressa. 
Rang’s Ocyropsis fusca is a uniformly light brownish or ocher- 
colored form from the Cape Verde Islands. It has not been seen since 
Rang described it in 1828. Itis possible that this may be an O. crystallina 
infested with commensal plant-cells, for such cells often infest the 
ctenophores of warm or tropical oceans, although they are unknown 
in species inhabiting cold seas. 
