38 CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 
Ocyropsis crystallina. (Figs. 55, 56, plate ro.) 
Ocyroé crystallina, RaNG, 1828, Mém. Soc. Nat. Paris, tome 4, 
. 172, plate 20, 
fig. 4—FEWKEs, 1882, Bull. Mus. Comp. Zool. at Hane College, vol. 9, 
No. 7, p. 252, plate 1, figs. 1-6.—MAayEr, 1900, Ibid., vol. 37, p. 81, plate 31, 
fig. 105.—MosEr, 1903, Ctenophoren der Siboga-Expedition, p. 17. 
Mature animal: (Text-figure 11.) The oral-aboral axis is about 
45 mm. long, and this is also the length of each oral lobe. The body is 
laterally compressed, the width in the direction of the oral lobes being 
about three times as great as that of the transverse axis. The 8 rows 
of ciliated plates are short and the plates are few in number. The 4 
subtentacular rows are only about two-thirds as long as the 4 subventral 
tows. Each subauricular row contains about 20 and each subventral row 
Es 
z 
as 
& 
: 
e 
Fic. 11.—Ocyropsis crystallina. Adult, ¢ natural size. 
Tortugas, Florida. 
about 4o ciliary plates. The cilia contribute but little to aid the animal 
in swimming, this being accomplished almost entirely by the flapping 
movements of the large, powerful, oral lobes, which by their periodic 
closure drive the animal forward. After two or three closures of the 
distended lobes there is usually a brief period of rest, followed by several 
more movements. A powerful system of radiating and circular muscles is 
found in the oral lobes and the flapping movements are caused by their 
contraction and expansion. The lobes are 1.5 times as wide as they are 
long. The simple apical sense-organ is sunken at the bottom of a shallow 
cleft. The auricles are each about 30 mm. in length, flat, and ribbon- 
like. Their narrow edges are lined with long cilia. Upon the outer 
surface of the oral lobes, immediately over the longitudinal meridional 
