KlllZOSTOM/B CASSIOPEA. 647 



Cassiopea frondosa Lamarck. 



Plate 69, figs. 1 to 3; plate 72, the 3 tipper figures. 



Medusa frotidosa, Pallas, 1774, Spicilegia Zoolog., fasc. 10, pp. 29, 30, plate 2, figs. 1-3. — Gmtlin, 1788, Liniie's .Syst. Naturae, 

 tomus I, pars 6, p. 3157. — Bosc, 1802, Hist. Nat. d Vers., tonic 2, p. 170. 



Caisiopea jrondosut Lamarck, 1816, Hist. Nat. Anim. sans Vert., tome 2, p. 512. — Eschscholtz, 1829, Syst. der Acalephen, 

 p. 43. — Tilesius, 1834, .Acad. Caes. Leop. Nova. Acta., torn. 15, pp. 263, 278, tab. 72, fign. 1-5. — Lesson, 1843, Zooph. 

 Acal., p. 405. — Milne-Edwards, 1849, Cuvier's Regne Animal, Zooph., plate 51, fig. 3. — Perkins, 1906, Year Book, 

 Carnegie Institution of Washington, No. 4, p. 115; 1908, Publication No. 102, Carnegie Institution of Washington, p. 152, 

 plate 4. 



Cassiopea pallasii, P£ron et Lesueur, 1808, Annal. der Mus. Hist. Nat., Paris, tome 14, p. 357, Nr. 85. 



Polyclonia frondosa, Agassiz, L., i860, Cont. Nat. Hist. U. S., vol. 3, plates 13, 13*2; 1S62, Ihid., vol. 4, pp. 139-148, 159. — 

 .■\gassiz, a., 1865, North .Amer. Acal., p. 41; 1 88 1, Nature, vol. 24, p. 509. See also .Archer, H., Ibid., p. 307. — Haeckel, 

 1880, Syst. der ^Icduscn, p. ij68; 1881, Report H. M. S. Challenger, Zool., vol. 4, p. xvill. — Vanhoffen, 1888, Bibliotheca 

 Zoologica, BJ. i, Heft. 3, p. 40. — Bigelow, R.P., 1893, Johns Hopkins University Circulars, vol. 2, No. 106, p. 106 (habits, 

 physiology). — Perkins, 1906, Year Book, Carnegie Institution of \\'ashington. No. 4, p. 115; 1908, Publication No. 102, 

 Carnegie Institution of Washington, p. 152. 



Disk flat, with rounded edge, and about 120 to 260 mm. in diameter. There is no con- 

 cavity at the center of the exumbrella, such as is seen in Cassiopea xamachana. There are 

 constcintly 12 marginal sense-organs in C. froiiJosa, 4 perradial, 8 adradial, each of which 

 contains a terminal entodermal mass of crystalHne concretions. There are no oceUi. There 

 are 60 short, subrectangular, nearly straight-edged, marginal lappets, 5 between each suc- 

 cessive pair of marginal sense-organs. The lappets flanking the sense-organs are only half 

 as wide as the other lappets. The 4 pairs of mouth-arms arise from a shallow, flat, mouth- 

 arm-disk at the center ot the subumbrella; this arm-disk is not quite as wide as the semi- 

 diameter of the medusa. The mouth-arms, which are about three-fourths as longas bell-radius, 

 usually bifurcate at their free ends and give rise to short, pinnate side branches from their 

 oral sides; but occasionalh' the branches are (juite long as in Casswpca xamachana. The 

 numerous frilled mouths are found exclusively upon their lower sides, the upper sides of the 

 mouth-arms being smooth and without mouths. Scattered quite uniformly between the mouths 

 are 30 to 40 small, expanded, flat, leaf-shaped vesicles. There are 4 small, round, interradial, 

 subgenital pits, and 4 separate, invaginated genital sacs which project into the stomach-cavity. 

 A duct extends from each of the 8 mouth-arms into the central stomach, and 24 radial-canals 

 pass outward from the stomach into the subumbrella and are put into communication one 

 with another by a network of anastomosing vessels. 12 radial-canals go to the marginal 

 sense-organs and 12 are intermediate in position. 



General color of gelatinous substance amber-yellow, slightl}- olive, or greenish. Just 

 above each of the 12 marginal sense-organs is usually a single, large, bilateral, bean-shaped 

 white spot in the gelatinous substance of the exumbrella. There is also a smaller white spot 

 in each marginal lappet, and above this an irregular line of 3 to 5 smaller white spots between 

 each successive pair of marginal sense-organs. A more or less broken, axial, white line extends 

 through the length of each mouth-arm in the gelatinous substance. The frilled mouths are 

 of a cinnamon color and the leaf-like vesicles are opatjue, dull white. The spots upon the 

 bell are very variable in number and arrangement (see plates 69 and ji). 



Cassiopea frondosa is found throughout the West Indian region and the Florida Reefs. 

 Perkins observes that it lives upon sand\' rather than weedy bottoms. In common with other 

 species of the genus it lies upon the bottom with the oral surface and mouth-arms uppermost. 

 In this position it remains for long intervals of time, slowly contracting its disk in a sluggish 

 rhythm. This movement serves not only to maintain the disk upon the bottom, but to create 

 a water-current over the mouth-arms. It prefers purer water than C. xamachana, and is usually 

 found in protected places among the mangroves in the cuts between the Florida Ke\s. 



In Kingston Harbor, Jamaica, this medusa is found upon the muddy bottoms of protected 

 lagoons, especially in those surrounded by mangroves, near the harbor entrance where the 

 water is quite pure. In Jamaica it attains to a far greater size than in Florida. A specimen 

 which I found in a mangrove lagoon near Port Royal in March, 1909, was of the following 

 dimensions in mm.: Bell 259 wide, arm-disk 95 wide, mouth-arms 129 long, pinnately and 

 complexly branched, and projecting be3ond the rim of the bell. Color as in the Florida 

 specimens. I am told that the medusa becomes even larger in Jamaica. 



L. Agassiz (1862, p. 147) showed that the young eph\ra of this species possesses a central 

 mouth-opening which disappears in the adult. 



