[23] MEDUSA FROM THE GULF STREAM. 949 



Ephyeoides eotafokmis, sp. nov. 



(Plate VII.) 



The different specimens of Ephyroides were regarded as members of a 

 single species, JE. rotaformis. Three specimens in the collection were 

 collected from Station 2044, and one from each of the others. None were 

 in the best of condition for a study of specific characters, and the char- 

 acter of the subumbrella was impossible to be made out with any great 

 accuracy. With one exception (Station 2042), the whole medusa was 

 covered with a brownish, coagulated slime, not unlike that found on the 

 surface of many specimens of Feriphylla (P. humilis), which rendered it 

 extremely difficult to study the minute anatomy. The generic characters 

 are, however, well marked on the exumbral surface of the umbrella of 

 all specimens. 



The umbrella is flat, discoid, and when seen from the exumbral side 

 appears divided into three zones: (1) Discus centralLs {dis. cent.)', 

 (2) Zona coronalis {cor.) ; (3) Zona marginalis {mg. Ip.). The diameter in 

 alcohol is about 15™"*. 



The zona centralis {dis. cent.), which corresponds to the central disk of 

 Atolla et alia, is circular, about 5°^™ in diameter. Its surface is smooth 

 and destitute of superficial appendages. No coronal fissure was observed 

 separating the discus centralis from the zona coronalis. 



The zona coronalis, {cor.) is, like the zona centralis, about 5™™ wide, 

 and bears upon its surface a number of radial elevations {soc), which 

 have suggested the name rotaformis, " wheel-formed," a resemblance 

 which is striking, shown in a specimen from Station 2042. These eleva- 

 tions vary in number in the different specimens, but are always found 

 in the radius which cuts the marginal fissures separating the marginal 

 lappets. They are simple, rounded, sausage-formed elevations, smooth 

 superficially, ending a short distance from the deepest point of the 

 marginal incision on the peripheral side, and abutting the line of junc- 

 tion of the discus centralis and zona coronalis, on the centripetal extrem- 

 ity. Their length varies slightly in different radii and in different speci- 

 mens. The resemblance which they impart to this region of the um- 

 brella and that of NaupJianta is striking. In all the specimens studied 

 the zona coronalis is extended horizontally, by which the elevations be- 

 come radial. Homology, when this genius is compared with the most 

 closely related genera, would lead us to believe that these bodies are 

 more vertical, although in Ephyra the homologous region is horizontal. 



The most peripheral of the three zones is the zone of the marginal 

 lappets, or the zona margiualis. The marginal lappets {mg. Ip.), as in all 

 Ephyridre, are prominent and large. Their walls are thin, outlines 

 rounded, twice as long as broad. The marginal lappets are sometimes 

 folded back on the e?:umbrella, when they lie in the spaces which sepa- 

 rate the radial elevations. The marginal lappets ( Fig. 2) are long, 

 thin, supported at their base by a pair of gelatinous socles (mg. soc.) 

 continuations with the walls of the bell. The tentacles in several cases 



