Chap. V. THE GENUS POLYCLONIA. 139 



and h% k*, It', h^, W, and 1^, corresponding to the ruffles 3, 4, 5, 6, 7, and 8 of Fig. 2. 

 A close examination of Fig. 4, however, shows that alternate arms differ in their 

 structure, c, c\ and c^ projecting more towards the central cavity of the oral cylinder 

 than the arms t and t^ ; this difference has no doubt reference to the primary 

 number of arms, which in all true Rhizostomidte is only four, dividing below the 

 j)illars, from which they arise, into eight, and each having its edges subdivided, as 

 Milne-Edwards' figure of Rhizostoma shows, in a manner which fully corresponds to 

 the complication of the ruffles and crested terminations of the oral tulje of Stomolo- 

 phus. An additional evidence of this quadripartite primary division is afforded by 

 the outline of the centre of the oral cylmder {^Fig. 3, s^ ^) leading into the main 

 digestive cavity. The umbrella is hemispherical, and its margin divided into eight 

 segments, by the presence of eight eyes, the outline of the edge of each segment 

 being crescent-shaped, and divided into twelve angular lobes. I know only one 

 species of this genus, which I have called Stomolophus meleagris, on account of 

 the spotted appearance of the marginal portion of the umbrella. The color seems 

 to be of a whitish blue, passing into a yellowish brown near the margin, the 

 marginal lobes being dark brown, as are also the spaces intervening between the 

 marginal spots. I say this seems to be the color of this Acaleph, because I have 

 only twice had an opportunity of seeing it, and, in both instances, under the most 

 unfavorable circumstances. The first time, I saw myriads of them (in April) stranded 

 upon the sand on the beach of Warsaw Island, below Savannah, in Georgia, all 

 of which had been exposed for hours to the sun, and were partially decomposed- 

 In most of them the umbrella and the arms, Avhich are of a very tough consist- 

 ency, seemed perfectly well jireserved. Many years afterwards, a specimen was 

 brought to me in Charleston, South Carolina, which had been found floating in 

 the harbor, in the latter part of May, and was in precisely the same state of 

 preservation as those I had seen before. Much remains, therefore, to be done in 

 the investigation of the internal structure of this interesting Medusa. 



SECTION III, 



THE GENUS POLYCLONIA. 



Under the name of Medusa frondosa, Pallas has described, from the Caribbean 

 Sea, in his " Spicilegia Zoologica," an Acaleph which Peron and LeSueur have after- 

 wards referred to the genus Cassiopea, in Avhich it was maintained by all later 

 writers. Mertens, on the other hand, has figured another Acaleph, which Brandt 



